Additives to prevent degradation of cyclic alkene derivatives

ABSTRACT

This disclosure relates to compositions that include (a) at least one substituted or unsubstituted cyclic alkene, and (b) an antioxidant composition including at least one compound of Formula (I): 
                         
R 1  through R 4  in Formula (I) are described in the specification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation and claims priority to U.S.application Ser. No. 12/498,726, filed Jul. 7, 2009, which is acontinuation-in-part and claims priority to U.S. application Ser. No.11/519,579, filed Sep. 12, 2006, which in turn claims priority to U.S.Provisional Application No. 60/716,102, filed Sep. 12, 2005. U.S.application Ser. No. 12/498,726 is also a continuation-in-part andclaims priority to U.S. application Ser. No. 11/519,524, filed Sep. 12,2006, which in turn claims priority to U.S. Provisional Application No.60/716,283, filed Sep. 12, 2005. U.S. application Ser. No. 12/498,726also claims priority from U.S. Provisional Application No. 61/078,984filed Jul. 8, 2008. The contents of the above-referenced applicationsare herein incorporated by reference.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

This disclosure relates generally to cyclic alkene compositions thatexhibit stability to air and/or heat. More particularly, this disclosureis directed to cyclic alkene derivatives stabilized with one or moreantioxidant compounds (e.g., substituted phenols) to reduce or eliminatepolymer formation upon exposure of a cyclic alkene composition tooxygen, heat or the two in combination, and methods for use of suchcompositions to form dielectric films.

2. Background of the Disclosure

The semiconductor industry requires numerous types of thin and thickfilms to prepare semiconductor devices, many of which are based onsilicon. The elemental composition of these films is typically somecombination of silicon and carbon with various combinations of oxygen,hydrogen, and fluorine. In U.S. Pat. No. 6,914,335, Andideh et al. teachhow layers can differ and can be used for different purposes, while inU.S. Pat. No. 6,846,515, Vrtis et al. teach ranges of silicon, oxygen,carbon and hydrogen for dielectric films preferred by the semiconductorindustry. A frequently used process is chemical vapor deposition, andthere are numerous variations of this process.

In a typical chemical vapor deposition process, a silicon containingcompound is introduced into a deposition chamber containing a substrateto be coated. The silicon containing compound is then chemically orphysically altered (i.e., reacted with another component, or subjectedto application of an energy source such as radiation, heat (thermalCVD), or plasma (PECVD), etc.) to deposit a film on the substrate.Deposited films containing only silicon and oxygen (i.e., silicon oxide)have a dielectric constant of approximately 4 in the absence of pores,while films that also contain carbon (i.e., carbon doped silicon oxide)and/or pores often have dielectric constants lower than 4. Films with adielectric constant below about 2.7 are preferred for newersemiconductor devices. In U.S. Pat. No. 6,583,048, Vincent et al.provide examples of chemical vapor deposition techniques, dielectricconstants, and examples of films that are desirable in the semiconductorindustry.

The properties of a layer deposited on a substrate, such as dielectricconstant, film hardness and refractive index, are influenced by changingthe composition of the chemistry that is fed into the film depositiontool and the process employed. The film properties can be tuned bychanging the identity of the silicon containing compound by using adifferent flow gas, by using one or more different reactive gases, or byusing post-deposition anneal techniques. Another means to affect thelayer properties is to use a combination of silicon containing compoundsor to combine a silicon containing compound(s) with one or more additivecompounds. These techniques can be employed to alter the chemicalcomposition of the film to adjust the film to the desired properties.U.S. Pat. Nos. 6,633,076, 6,217,658, 6,159,871, 6,479,110 and 6,756,323,herein incorporated by reference, give examples of how film propertiesare affected by changing deposition parameters or component mixtures.

An alternative use for the additive compound is to provide compoundswhose fragments or atoms are only temporarily resident in the film. Thefilm can be post-treated to drive the fragments or atoms out of the filmusing heat, radiation or a combination of heat or radiation and reactivegases, such as oxygen, to create pores in the resulting film. Thisapproach affects the properties (e.g. dielectric constant) of thedeposited film. The compounds employed in this manner are described asporogens.

Typical porogens used in this type of approach are predominatelycomposed of carbon and hydrogen. Examples of some of the classes ofcyclic alkene compounds of interest as porogens are described in U.S.Pat. Nos. 6,846,515 and 6,756,323.

High volume semiconductor manufacturing places stringent demands on theequipment and on the purity and stability of the chemistries that flowthrough the equipment. A chemical that is sent through chemical linesand a vaporizer means is expected to transport and vaporize cleanly andleave behind little or no residue during extended use. The longer apiece of equipment can operate between scheduled or unscheduledmaintenance periods (e.g., to clean out or replace chemical lines or avaporizer means that is fouled or clogged with polymeric or otherresidue), the more productive the tool is, making it morecost-effective. A deposition tool that must be shut down often forcleaning and maintenance is not as appealing to semiconductormanufacturing customers. Thus, continuous, long term operation ofequipment is desirable. Vaporizer means can include several types ofvaporization apparatuses, including, but not limited to, heatedvaporizers (see, e.g., U.S. Pat. Nos. 6,604,492, 5,882,416, 5,835,678and references therein), bubbler ampoules (see, e.g., U.S. Pat. Nos.4,979,545, 5,279,338, 5,551,309, 5,607,002, 5,992,830 and referencestherein), flash evaporators (see, e.g., U.S. Pat. No. 5,536,323 andreferences therein) and misting apparatuses (see, e.g., U.S. Pat. Nos.5,451,260, 5,372,754, 6,383,555 and references therein).

1,3,5,7-Tetramethylcyclotetrasiloxane (TMCTS) is a representativesilicon containing compound which can be employed to produce low kdielectric films and is an example of the difficulty in maintainingstability. Initial work to establish reliable manufacturing processeswas hampered by the product gelling at different points in thedeposition process, including the chemical lines, vapor delivery lines,and within the deposition chamber. This indicated that the stability ofpure TMCTS was not sufficient, and a variety of additives were studiedby Teff et al. in U.S. Pat. Nos. 7,129,311 and 7,531,590, which areincorporated herein by reference. It was found that antioxidants werehighly effective to stabilize TMCTS against exposure to air,specifically oxygen, for extended periods of time at ambient or elevatedtemperatures. When antioxidant-stabilized TMCTS is used now insemiconductor manufacturing, processes are more stable, and gelformation in a deposition tool is reduced significantly.

Norbornadiene (NBDE) is an example of a cyclic diene of interest for useas a porogen primarily due to the bond strain in its structure and itstendency to undergo thermal reactions to form volatile materials whenheated (see, e.g., U.S. Pat. Nos. 6,846,515, 6,479,110, 6,437,443, and6,312,793). NBDE and similar cyclic alkene derivatives can react withoxygen to either polymerize or oxidize, forming higher molecular weight,lower volatility materials which may or may not be soluble in the cyclicalkene monomer. This reaction can cause significant degradation of thecyclic alkene over time, even after brief air exposure at roomtemperature.

NBDE forms highly soluble, low volatility solid products in the presenceof adventitious air, in the presence of heat, or when the two arecombined. While evidence of thermal degradation has been observed insamples heated at 120° C. for 24 hours, oxidative degradation has beenobserved in samples kept at room temperature or samples that were heatedto 80° C. or more. These are very important factors to consider, sinceit only takes trace oxygen (low ppb level) to form enough residue (lowppm level) to become problematic during semiconductor processing. Thecombined difficulty of completely eliminating oxygen from a product withthe need to use heat to evaporate the product during semiconductorprocessing makes it nearly impossible to avoid forming low volatilityresidue without an effective stabilizer. This can result in accumulationof the solid product in a vaporizer means as the volatile NBDE isevaporated away. If the surface area of the vaporizer means is small, itis possible that small amounts of residue (e.g., at a milligrams level)can hinder the evaporation of NBDE, eventually causing the vaporizermeans to clog with the low volatility solids. If a bubbler ampoule isemployed as the vaporizer means, oxidation products could initiate apolymerization process, causing the entire contents of the bubbler topolymerize and block the flow gas inlet line. This is especially truewith bubblers that are constantly heated to assist the vaporizationprocess. The only remedy is to disassemble and clean or replace theaffected vaporizer means, which is very costly and time consuming.Safety issues are also a concern if pressurized chemical lines andvalves become blocked with the low volatility solid.

While NBDE is being used in semiconductor manufacturing, equipment maygo idle from time to time for various reasons (e.g., power fluctuation,holiday shutdown, etc). During this idle time, a portion of product(usually <1 mL) may be kept in a heated zone at temperatures up to 85°C. for several hours or days. During this time, the product can formsoluble, nonvolatile residue that will accumulate in the vaporizer whenthe equipment is restarted. Therefore, an effective NBDE containingcomposition must be thermally stable for periods of hours or days.

The standard manufacturing process for a product such as stabilized NBDEinvolves a significant number of chemical handling steps. Since eachhandling step (and subsequent storage period) is not completely free ofair, product will almost always be exposed to trace amounts of oxygenduring its lifetime. As mentioned previously, it takes only a traceamount of oxygen to give an unacceptable level of residue. Therefore, aneffective NBDE product must also be stabilized against oxygen-induceddegradation for a period of time (potentially one or more years) inorder for it to have an acceptable shelf life.

The semiconductor industry requires stable, predictable and reliableproducts, and even a relatively low level of this decomposition isunacceptable for high volume semiconductor manufacturing. Therefore, itis necessary to find a means to stabilize NBDE to ensure that theproduct does not easily decompose during transport from the chemicalsupplier to the end-use process, even after exposure to variousconditions. However, chemistry of the cyclic alkene compounds differsconsiderably from the chemistry of the silicon containing compoundstypically employed, so it is not obvious that the same compounds thatstabilize the silicon containing compounds will stabilize the cyclicalkene compounds.

TMCTS is believed to ring open and polymerize in the presence of oxygen.Further, TMCTS has Si—H bonds that are reactive with molecular oxygen(see, e.g., US Patent Application No. 20040127070 and U.S. Pat. No.6,858,697). By contrast, NBDE will slowly oligomerize in the presence ofair, but it will not gel and the ring structure remains intact duringthe oligomerization process. Where TMCTS can completely polymerize as agel inside a chemical line upon exposure to air, NBDE instead forms ahighly soluble, medium to high molecular weight and low volatilityoligomer that is not apparent upon visual inspection, or easilydetectable by gas chromatography (GC). Instead, the resulting oligomersare detected when the volatile NBDE is evaporated away to leave behindthe low volatility oligomers.

NBDE and similar materials are sometimes stabilized with antioxidants,such as 2,6-di-tert-butyl-4-methoxyphenol (BHA) or2,6-di-tert-butyl-4-methylphenol (BHT), (see Clariant LSM 171779Norbornadiene Specification Sheet and Aldrich Catalog Number B3, 380-3).The known antioxidants for these materials have very high boilingpoints, (b.p. of BHT is 265° C.), and may have atoms not desired to bein incorporated into the deposited film (e.g. sulfur, nitrogen). Theseantioxidants are commonly added at concentrations of 0.02 to 0.25 wt %(200 to 2,500 ppm), but additives can exceed this amount when themanufacturer wants to increase shelf life. Chemical manufacturers preferto use BHT due to its low cost and availability. However, theconcentrations of these additives are higher than desired forsemiconductor purposes. In U.S. Patent Application Nos. 20070057234 and20070057235 (both herein incorporated by reference), Teff et al.demonstrated results using the antioxidant 4-methoxyphenol at lowerconcentrations.

SUMMARY OF THE DISCLOSURE

In one aspect, this disclosure provides a composition including (a) oneor more substituted or unsubstituted cyclic alkenes, and (b) anantioxidant composition including at least one compound of Formula (I):

in which R¹ through R⁴ can each independently be H, C₁-C₈ linear alkyl,C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈cyclic alkoxy or substituted or unsubstituted aryl.

In another aspect, this disclosure provides a composition including (a)one or more substituted or unsubstituted cyclic alkenes, and (b) anantioxidant composition including at least one compound of Formula (I),in which R¹ through R⁴ can each independently be H, C₁-C₈ linear alkyl,C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈cyclic alkoxy or substituted or unsubstituted aryl with the proviso thatat least one of R¹ through R⁴ is not H, and/or that, if one of R¹through R⁴ is t-butyl, at least one of the remaining R¹ through R⁴ isnot H. In some embodiments, the compound of Formula (I) can be4-methyl-1,2-dihydroxybenzene or 3-methoxy-1,2-dihydroxybenzene

In still another aspect, this disclosure provides a composition thatincludes (a) a cyclic alkene selected from the group consisting ofdipentene, phellandrene, dicyclopentadiene, alpha-terpinene,gamma-terpinene, limonene, alpha-pinene, 3-carene, terpinolene,norbornene, norbornadiene, 5-vinyl-2-norbornene, and5-ethylidene-2-norbornene; and (b) an antioxidant composition comprising4-methyl-1,2-dihydroxybenzene or 3-methoxy-1,2-dihydroxybenzene. Theantioxidant composition is present in a concentration between about 50ppm and about 200 ppm (e.g., 100 ppm).

In still another aspect, this disclosure provides an apparatuscontaining a sealed container including a cyclic alkene composition. Thecyclic alkene composition contains (a) at least one substituted orunsubstituted cyclic alkene, and (b) at least one antioxidantcomposition, in which the cyclic alkene composition generates at mostabout 200 ppm (e.g., at most about 150 ppm, at most about 100 ppm, atmost about 50 ppm, or at most about 10 ppm) of residue after one year ofstorage in the sealed container at room temperature.

In still another aspect, this disclosure provides an apparatus thatincludes a sealed container containing from about 0 ppm to about 150 ppmoxygen and a cyclic alkene composition. The cyclic alkene compositionincludes (a) at least one substituted or unsubstituted cyclic alkene,and (b) at least one antioxidant composition, in which the cyclic alkenecomposition generates at most about 20 ppm of residue after being heatedat 80° C. for 12 hours in the sealed container. For example, when thesealed container contains about 150 ppm oxygen, the cyclic alkenecomposition can generate at most about 20 ppm of residue after beingheated at 80° C. for 12 hours in the sealed container. As anotherexample, when the sealed container contains about 25 ppm oxygen, thecyclic alkene composition can generate at most about 5 ppm (e.g., atmost about 0.5 ppm) of residue after being heated at 80° C. for 12 hoursin the sealed container. As another example, when the sealed containercontains about 0 ppm oxygen, the cyclic alkene composition can generateat most about 5 ppm (e.g., at most about 0.5 ppm) of residue after beingheated at 80° C. for 12 hours in the sealed container.

In still another aspect, this disclosure provides an apparatus thatincludes a sealed container containing from about 0 ppm to about 150 ppmoxygen and a cyclic alkene composition. The cyclic alkene compositionincludes (a) at least one substituted or unsubstituted cyclic alkene,and (b) at least one antioxidant composition, in which the cyclic alkenecomposition generates at most about 200 ppm of residue after beingheated at 120° C. for 24 hours in the sealed container. For example,when the sealed container includes about 0 ppm oxygen, the cyclic alkenecomposition can generate at most about 200 ppm (e.g., at most about 160ppm) of residue after being heated at 120° C. for 24 hours in the sealedcontainer.

In still another aspect, this disclosure provides a process using acyclic alkene composition for forming a layer of carbon-doped siliconoxide on a wafer. The process includes treating a substrate in a filmdeposition chamber with a composition containing at least one of theabove-mentioned cyclic alkene compositions and at least one siliconcontaining compound to form a carbon doped silicon oxide film on thesubstrate. The composition can also include other additives. The processcan further include, prior to the treatment step, providing the cyclicalkene composition in a first container, the silicon containing compoundin a second container, a film deposition tool containing the filmdeposition chamber, a gas delivery line for connecting the first andsecond containers to the film deposition chamber within the filmdeposition tool, and a stream of carrier gas to sweep the cyclic alkenecomposition and the silicon containing compound through the gas deliveryline into the film deposition chamber; introducing vapors of the cyclicalkene composition and the silicon containing compound into the carriergas stream; and transporting the vapors of the cyclic alkene compositionand silicon containing compound into the film deposition chamber via thecarrier gas stream.

In still another aspect, this disclosure provides a process thatincludes storing at least one of the above-mentioned cyclic alkenecompositions in a sealed container for at least 6 months (e.g., at least9 months or at least one year), and after storing the cyclic alkenecomposition, using the cyclic alkene composition together with at leastone silicon-containing compound in a chemical vapor deposition processto form a carbon doped silicon oxide film on a substrate.

In still another aspect, this disclosure provides a process forstabilizing a cyclic alkene. The process includes adding at least onecompound of Formula (I) described above to the cyclic alkene. In someembodiments, adding at least one compound of Formula (I) can be carriedout by, among other steps, (a) adding the at least one compound ofFormula (I) in a receiving vessel in a distillation system for purifyingthe cyclic alkene, and (b) distilling the cyclic alkene through thedistillation system into the receiving vessel. In some embodiments,adding at least one compound of Formula (I) can be carried out by, amongother steps, (a) adding the at least one compound of Formula (I) at apoint between a condenser and a receiving vessel in a distillationsystem for purifying the cyclic alkene, and (b) distilling the cyclicalkene through the distillation system so that the distilled cyclicalkene passes from the condenser into the receiving vessel, therebysolubilizing the at least one compound of Formula (I) in the distilledcyclic alkene. In some embodiments, adding at least one compound ofFormula (I) can be carried out by, among other steps, (a) distilling thecyclic alkene through a distillation system into a receiving vessel, and(b) adding the at least one compound of Formula (I) into the receivingvessel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a representation of a film deposition tool used in thesemiconductor industry for use with the compositions according to thisdisclosure, where two independent vaporizer means are used with twoseparate precursors.

FIG. 2 is a representation of a film deposition tool used in thesemiconductor industry for use with the compositions according to thisdisclosure, where a single vaporizer means is used with two separateprecursors.

FIG. 3 is a plot showing the residue concentration of four samples ofNBDE stabilized with 50 ppm of MHQ as a function of sample age.

FIG. 4 is a plot showing the residue concentration of four samples ofNBDE stabilized with 100 ppm of 4-MCAT as a function of sample age.

FIG. 5 is a plot including both plots shown in FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE DISCLOSURE

The semiconductor industry requires numerous types of thin and thickfilms to prepare semiconductor devices. A frequently used process toprepare these films is chemical vapor deposition and there are numerousvariations of this process. In a typical chemical vapor depositionprocess, a silicon containing compound is introduced into a depositionchamber containing the substrate to be coated. The silicon containingcompound is then chemically or physically altered (reacted with anothercomponent, or subjected to application of an energy source such asradiation, heat (thermal CVD), or plasma (PECVD), etc.) to deposit thefilm on the substrate.

These purity and stability requirements are often difficult to achieve.Many materials may oxidize, polymerize or rearrange to some degree. Evensmall amounts (e.g., more than 200 ppm) of such byproducts may beundesirable for many semiconductor applications. Thus materials used inthe semiconductor industry may require additives to prevent formation ofundesired side reactions before reaching a deposition chamber.

Cyclic alkenes are materials of interest as reagents for chemical vapordeposition to form low k dielectric films in the semiconductor industrybut require additives to be stabilized to maintain high purity duringthe shelf life of the product.

Chemicals, including additives, that are useful for the semiconductorindustry are typically limited to species that have a boiling pointlower than 300° C. Furthermore, the specific application in thesemiconductor industry may dictate additional properties of theprecursor must have. For example, formation of interlayer dielectric(ILD) films restricts precursor selection to use only silicon, oxygen,carbon and hydrogen due to compatibility issues with surrounding layersin a chip. The selection of radical inhibitors must also follow thisbasis, so nitrogen, sulfur and phosphorous that are found in commonradical inhibitors and antioxidants such as lecithin and lipoic acidmust be avoided.

In some embodiments, it is advantageous to minimize the boiling pointdifference between the cyclic alkenes and the stabilizer that is used.For example, NBDE boils at 89° C. while BHT boils at 265° C. Thisdifference is enough to cause significant problems in a semiconductordeposition tool vaporizer means. Commonly, these vaporizer means are setat the lowest possible temperature to allow complete vaporization of aliquid product while avoiding thermal decomposition. It is alsonecessary to balance thermal loading of the vaporizer means to correctlyvaporize the product without saturating a vapor stream. With theseconsiderations, it is a fine balance to vaporize the source chemicalwithout adding too much heat. Thus, it is most often the case thathigher molecular weight components are poorly vaporized, or notvaporized at all, and these tend to accumulate in the vaporizer means toeventually clog it. For this reason, it is desirable to reduce thedifference between the boiling points of cyclic alkene derivatives andtheir stabilizers, and to reduce the concentrations of the stabilizersto their lowest effective levels.

This disclosure relates to cyclic alkene compositions that arestabilized by the addition of specific unsubstituted or substituteddihydroxybenzene compounds surprisingly found to have higher stabilizingcapability than prior art monohydroxybenzene compounds. The resultingcompositions exhibit enhanced stability and significantly extend theshelf life of cyclic alkene products, allowing greater flexibility inhandling these products in semiconductor manufacturing. The resultingstabilization of cyclic alkenes using more active stabilizers reducesthe formation of soluble polymers in the final product. In turn, thisdrastically reduces the accumulation of soluble polymers in chemicaldelivery lines, in valves, or in vaporizer means. This reduces the needfor equipment maintenance, reduces costs and reduces time the machineryis out of use for production. In addition, reducing the formation ofhigher molecular weight compounds allows for homogeneous vaporization ofthe product without concern for the gradual deposition of highermolecular weight compounds in vapor delivery lines, leading to moreconsistent, higher quality deposited films on the wafer. In someembodiments, the use of more volatile antioxidants (e.g., antioxidantswith a relative low melting or boiling point) is also advantageous,since there is a greater likelihood that the cyclic alkene and thevolatile stabilizer will be cleanly evaporated and cleanly deliveredthrough a chemical delivery line, leading to a cleaner process. Forexample, when a chemical delivery line is heated so that the cyclicalkene composition can be delivered as a liquid or a vapor, the heatingmay not be uniform and homogeneous resulting in undesirable cold spotswhere the temperature is lower than in the rest of the delivery line.Even in the presence of such cold spots, an antioxidant with a lowermelting or boiling point can stay liquefied or vaporized, therebyreducing contamination of the delivery line at the cold spots by theantioxidant during the delivery process.

In one embodiment of this disclosure, the cyclic alkene compositionincludes (a) one or more substituted or unsubstituted cyclic alkenes,and (b) an antioxidant compound shown in Formula (I),

in which R¹ through R⁴ can each independently be H, C₁-C₈ linear alkyl,C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈cyclic alkoxy or substituted or unsubstituted aryl with the proviso thatat least one of R¹ through R⁴ is not H, and that, if one of R¹ throughR⁴ is t-butyl, at least one of the remaining R¹ through R⁴ is not H.

Cyclic alkene is hereby defined as any carbocyclic compound having anonaromatic double bond in a nonaromatic ring. Examples of classes ofcyclic alkene include, but are not limited to cycloalkenes,cycloalkadienes, cycloalkatrienes, cycloalkatetraenes,aromatic-containing cycloolefins, polycyclic alkenes, polycyclicalkadienes, polycyclic alkatrienes, polycyclic alkatetraenes, andmixtures thereof.

A preferred class of cyclic alkenes are singly or multiply unsaturatedcyclic alkenes of the general formula C_(n)H_(2n−2x−y)R_(y) where n isthe number of carbons in the primary cyclic structure, x is the numberof unsaturated sites in the primary cyclic structure, and y is thenumber of substituents, R, on the primary cyclic structure. In thisclass of cyclic alkenes, n ranged from 4 to 18, x is an integer and1≦x≦n/2, y is an integer and 0≦y≦2n−2x, and each R can independently beC₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl,C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy,C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted orunsubstituted aryl, or substituted silicon containing substituent.Examples of this class include, but are not limited to,t-butylcyclohexene, alpha-terpinene, limonene, gamma-terpinene,1,5-dimethyl-1,5-cyclooctadiene, vinylcyclohexene, cyclobutene,methylcyclobutene, dimethylcyclobutene, trimethylcyclobutene,ethylcyclobutene, diethylcyclobutene, triethylcyclobutene,methoxycyclobutene, methylmethoxycyclobutene, cyclohexylcyclobutene,isopropylcyclobutene, isopropenylcyclobutene, cyclopentene,methylcyclopentene, dimethylcyclopentene, trimethylcyclopentene,methoxycyclopentene, methylmethoxycyclopentene, cyclohexylcyclopentene,isopropylcyclopentene, isopropenylcyclopentene, cyclopentadiene,methylcyclopentadiene, dimethylcyclopentadiene,trimethylcyclopentadiene, methoxycyclopentadiene,methylmethoxycyclopentadiene, cyclohexylcyclopentadiene,isopropylcyclopentadiene, isopropenylcyclopentadiene, cyclohexene,methylcyclohexene, dimethylcyclohexene, trimethylcyclohexene,methoxycyclohexene, methoxymethylcyclohexene, cyclohexylcyclohexene,isopropylcyclohexene, isopropenylcyclohexene, cyclohexadiene,methylcyclohexadiene, dimethylcyclohexadiene, trimethylcyclohexadiene,methoxycyclohexadiene, methoxymethylcyclohexadiene,cyclohexylcyclohexadiene, isopropylcyclohexadiene,isopropenylcyclohexadiene, cycloheptene, methylcycloheptene,dimethylcycloheptene, trimethylcycloheptene, methoxycycloheptene,methoxymethylcycloheptene, cyclohexylcycloheptene,isopropylcycloheptene, isopropenylcycloheptene, cycloheptadiene,methylcycloheptadiene, dimethylcycloheptadiene,trimethylcycloheptadiene, methoxycycloheptadiene,methoxymethylcycloheptadiene, cyclohexylcycloheptadiene,isopropylcycloheptadiene, isopropenylcycloheptadiene, cycloheptatriene,methylcycloheptatriene, dimethylcycloheptatriene,trimethylcycloheptatriene, methoxycycloheptatriene,methoxymethylcycloheptatriene, cyclohexylcycloheptatriene,isopropylcycloheptatriene, isopropenylcycloheptatriene, cyclooctene,methylcyclooctene, dimethylcyclooctene, trimethylcyclooctene,methoxycyclooctene, methoxymethylcyclooctene, cyclohexylcyclooctene,isopropylcyclooctene, isopropenylcyclooctene, cyclooctadiene,methylcyclooctadiene, dimethylcyclooctadiene, trimethylcyclooctadiene,methoxycyclooctadiene, methoxymethylcyclooctadiene,cyclohexylcyclooctadiene, isopropylcyclooctadiene,isopropenylcyclooctadiene, cyclooctatriene, methylcyclooctatriene,dimethylcyclooctatriene, trimethylcyclooctatriene,methoxycyclooctatriene, methoxymethylcyclooctatriene,cyclohexylcyclooctatriene, isopropylcyclooctatriene,isopropenylcyclooctatriene, cyclooctatetraene, methylcyclooctatetraene,dimethylcyclooctatetraene, trimethylcyclooctatetraene,methoxycyclooctatetraene, methoxymethylcyclooctatetraene,cyclohexylcyclooctatetraene, isopropylcyclooctatetraene,isopropenylcyclooctatetraene, 3-phenyl-1-cyclohexene,3-(2-methoxyphenyl)-1-cyclohexene, 3-cyclohexenyltrimethylsilane,3-cyclohexenyltrimethoxysilane,[2-(3-cyclohexenyl)ethyl]trimethoxysilane,[2-(3-cyclohexenyl)ethyl]triethoxysilane, tert-butylcyclohexene,p-menth-1-ene, phellandrene, and terpinolene.

Another preferred class of suitable cyclic alkenes is bicyclic alkenesof the general formula C_(n)H_(2n−(2x+2)−y)R_(y) where n is the numberof carbons in the primary bicyclic structure, x is the number ofunsaturated sites in the primary bicyclic structure, and y is the numberof substitutions, R, on the primary bicyclic structure. In this class ofcyclic alkenes, n can range from 5 to 18, x is an integer and x≦n/2, yis an integer and 0≦y≦2n−(2x+2), and each R can independently be C₁-C₁₈linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstitutedaryl, or substituted silicon containing substituent. Examples of thisclass include, but are not limited to, 3-carene, alpha-pinene,norbornene, norbornadiene, bicyclo[2.2.2]octa-2,5,7-triene,[(bicycloheptenyl)ethyl]trimethoxysilane, hexamethyldewarbenzene,bicyclo[4.3.0]nona-3,7-diene, 1,4,5,8-tetrahydronaphthalene,2,3-dimethyl-1,4,5,8-tetrahydronaphthalene,bicyclo[4.3.0]nona-3,7-diene, bicyclo[4.1.1]oct-3-ene,bicyclo[4.2.0]oct-3-ene, bicyclo[4.2.0]octa-2,4-diene,5-(bicyclo[2.2.1]hept-2-enyl)triethoxysilane,bicyclo[4.2.0]octa-2,7-diene, bicyclo[4.3.0]nona-3,6-diene,5-vinyl-2-norbornene and 5-ethylidene-2-norbornene.

Another preferred class of cyclic alkenes is tricyclic alkenes of thegeneral formula C_(n)H_(2n−(2x+4)−y)R_(y) where n is the number ofcarbons in the primary tricyclic structure, x is the number ofunsaturated sites in the primary tricyclic structure, and y is thenumber of substitutions, R, on the primary tricyclic structure. In thisclass, n can range from 7 to 18, x is an integer and x≦n/2, y is aninteger and 0≦y≦2n−(2x+4), each R can independently be C₁-C₁₈ linearalkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclicalkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturatedalkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, orsubstituted silicon containing substituent. Examples include, but arenot limited to, dicyclopentadiene,1,2,3,4,4A,5,8,8A-octahydro-1,4-methanonaphthalene,octamethyltricyclo[4.2.0.0(2,5)]octa-3,7-diene,1,4-dihydro-1,4-methanonaphthalene and [4.2.2]propella-2,4,7,9-tetraene.

Examples of R in each of the three classes of preferred cyclic alkenesdescribed above include, but are not limited to, methyl, ethyl, propyl,isopropyl, isopropenyl, butyl, phenyl, methylphenyl, trimethylsilyl,cyclohexyl, methoxy, ethoxy, propoxy, isopropoxy, isopropenoxy, butoxy,phenoxy, methylphenoxy, trimethylsiloxy, or cyclohexloxy. Preferredexamples of R include methyl, isopropyl, and isopropenyl. Methyl,isopropyl and isopropenyl are most preferred for R for use insemiconductor applications.

Preferred cyclic alkenes include dipentene, phellandrene,dicyclopentadiene, alpha-terpinene, gamma-terpinene, limonene,alpha-pinene, 3-carene, terpinolene, norbornene, norbornadiene,5-vinyl-2-norbornene, and 5-ethylidene-2-norbornene. The most preferredcyclic alkenes are dicyclopentadiene, alpha-terpinene, norbornene,norbornadiene, 5-vinyl-2-norbornene, and 5-ethylidene-2-norbornene.

Suitable antioxidants of the present disclosure are described by Formula(I), in which R¹ through R⁴ can each independently be H, C₁-C₈ linearalkyl, C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclicalkyl, C₁-C₈ linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branchedalkoxy, C₃-C₈ cyclic alkoxy or substituted or unsubstituted aryl withthe proviso that R¹ through R⁴ do not all equal H and that if one of R¹through R⁴ is t-butyl, at least one of the remaining R¹ through R⁴ isnot H. Preferred ranges of R¹ through R⁴ in Formula (I) include H, C₁-C₃linear alkyl, C₃-C₄ branched alkyl, and C₁-C₂ linear alkoxy consideringthe aforementioned proviso. More preferred ranges of R¹ through R⁴ inFormula (I) include H, C₁-C₂ linear alkyl, C₄ branched alkyl, and C₁linear alkoxy considering the aforementioned proviso. Most preferredranges of R¹ through R⁴ in Formula (I) include H, C₁ linear alkyl, C₄branched alkyl, and C₁ linear alkoxy considering the aforementionedproviso. Examples of suitable R¹ through R⁴ include, but are not limitedto, H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl,cyclohexyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxytert-butoxy, cyclohexyloxy, phenyl or methylphenyl. Preferred examplesof R¹ through R⁴ in Formula (I) include H, methyl, ethyl, methoxy,ethoxy, propyl, isopropyl, isobutyl, and tert-butyl. More preferredexamples of R¹ through R⁴ in Formula (I) include H, methyl, ethyl,methoxy, and tert-butyl. Most preferred examples of R¹ through R⁴ inFormula (I) include H, methyl, methoxy and tert-butyl.

Suitable examples of Formula (I) include, but are not limited to,3-methyl-1,2-dihydroxybenzene, 4-methyl-1,2-dihydroxybenzene (4-MCAT,which has a boiling point of about 251° C.),3-ethyl-1,2-dihydroxybenzene, 4-ethyl-1,2-dihydroxybenzene,3-propyl-1,2-dihydroxybenzene, 4-propyl-1,2-dihydroxybenzene,3-isopropyl-1,2-dihydroxybenzene, 4-isopropyl-1,2-dihydroxybenzene,3-butyl-1,2-dihydroxybenzene, 4-butyl-1,2-dihydroxybenzene,3-isobutyl-1,2-dihydroxybenzene, 4-isobutyl-1,2-dihydroxybenzene,3-cyclohexyl-1,2-dihydroxybenzene, 4-cyclohexyl-1,2-dihydroxybenzene,3-methoxy-1,2-dihydroxybenzene (3-MOCAT),4-methoxy-1,2-dihydroxybenzene, 3-ethoxy-1,2-dihydroxybenzene,4-ethoxy-1,2-dihydroxybenzene, 3-propoxy-1,2-dihydroxybenzene,4-propoxy-1,2-dihydroxybenzene, 3-isopropoxy-1,2-dihydroxybenzene,4-isopropoxy-1,2-dihydroxybenzene, 3-butoxy-1,2-dihydroxybenzene,4-butoxy-1,2-dihydroxybenzene, 3-isobutoxy-1,2-dihydroxybenzene,4-isobutoxy-1,2-dihydroxybenzene, 3-tert-butoxy-1,2-dihydroxybenzene,4-tert-butoxy-1,2-dihydroxybenzene,3-cyclohexyloxy-1,2-dihydroxybenzene,4-cyclohexyloxy-1,2-dihydroxybenzene, 3-phenyl-1,2-dihydroxybenzene,4-phenyl-1,2-dihydroxybenzene, 3-(4-methylphenyl)-1,2-dihydroxybenzene,4-(4-methylphenyl)-1,2-dihydroxybenzene,3-tert-butyl-4-methyl-1,2-dihydroxybenzene,3-methyl-4-tert-butyl-1,2-dihydroxybenzene,3-tert-butyl-4-methoxy-1,2-dihydroxybenzene,3-methoxy-4-tert-butyl-1,2-dihydroxybenzene,3-allyl-4-methoxy-1,2-dihydroxybenzene,3-methoxy-4-allyl-1,2-dihydroxybenzene,3-allyl-4-methyl-1,2-dihydroxybenzene,3-methyl-4-allyl-1,2-dihydroxybenzene,3,4-dimethyl-1,2-dihydroxybenzene, 3,6-dimethyl-1,2-dihydroxybenzene,3,5-dimethyl-1,2-dihydroxybenzene,3,6-dimethyl-4,5-dimethoxy-1,2-dihydroxybenzene and4-methyl-3-methoxy-dihydroxybenzene. Preferred antioxidants of Formula(I) include 3-methyl-1,2-dihydroxybenzene,4-methyl-1,2-dihydroxybenzene, 3-methoxy-1,2-dihydroxybenzene,4-methoxy-1,2-dihydroxybenzene, 3-propyl-1,2-dihydroxybenzene,4-propyl-1,2-dihydroxybenzene, 3-isopropyl-1,2-dihydroxybenzene,4-isopropyl-1,2-dihydroxybenzene, 3-isobutyl-1,2-dihydroxybenzene,4-isobutyl-1,2-dihydroxybenzene,3-tert-butyl-4-methyl-1,2-dihydroxybenzene,4-tert-butyl-3-methyl-1,2-dihydroxybenzene,3,4-dimethyl-1,2-dihydroxybenzene, 3,6-dimethyl-1,2-dihydroxybenzene,3,5-dimethyl-1,2-dihydroxybenzene, 3-ethyl-1,2-dihydroxybenzene,4-ethyl-1,2-dihydroxybenzene, 3-ethoxy-1,2-dihydroxybenzene, and4-ethoxy-1,2-dihydroxybenzene. More preferred antioxidants of Formula(I) are 3-methyl-1,2-dihydroxybenzene, 4-methyl-1,2-dihydroxybenzene,3-ethyl-1,2-dihydroxybenzene, 4-ethyl-1,2-dihydroxybenzene,3-methoxy-1,2-dihydroxybenzene, 4-methoxy-1,2-dihydroxybenzene,3-tert-butyl-4-methyl-1,2-dihydroxybenzene,4-tert-butyl-3-methyl-1,2-dihydroxybenzene,3,4-dimethyl-1,2-dihydroxybenzene, 3,6-dimethyl-1,2-dihydroxybenzene,and 3,5-dimethyl-1,2-dihydroxybenzene. Most preferred antioxidants ofFormula (I) are 3-methyl-1,2-dihydroxybenzene,4-methyl-1,2-dihydroxybenzene, 3-methoxy-1,2-dihydroxybenzene,4-methoxy-1,2-dihydroxybenzene,3-tert-butyl-4-methyl-1,2-dihydroxybenzene,4-tert-butyl-3-methyl-1,2-dihydroxybenzene,3,4-dimethyl-1,2-dihydroxybenzene, 3,6-dimethyl-1,2-dihydroxybenzene,and 3,5-dimethyl-1,2-dihydroxybenzene.

A suitable concentration of an antioxidant of Formula (I) can range fromabout 1 ppm to about 200 ppm. Suitable concentration ranges can bedefined by defining a low end of suitable concentrations and a high endof suitable concentrations.

The low end of the suitable concentration range for an antioxidant ofFormula (I) can be any value from about 1 ppm to about 50 ppm. Forexample, suitable concentrations for the low end concentration rangeinclude, but are not limited, to 1 ppm, 5 ppm, 10 ppm, 25 ppm and 50ppm. If the amount of the antioxidant is too small, the antioxidant maynot provide enough stabilization effect to the composition to bestabilized.

The high end of the suitable concentration range can be limited by someconsiderations, such as the deposited film purity, the amount ofimpurity in an antioxidant of Formula (I), and solubility of anantioxidant of Formula (I) in the cyclic alkene composition. Forexample, because an antioxidant could itself contain impurity, includinga large amount of the antioxidant into a composition could introduce alarge amount of impurity, thereby resulting in a decrease in thestability of the composition. A high end of the concentration of anantioxidant of Formula (I) can be any value from about 100 ppm to about200 ppm. Examples of suitable high end concentrations include, but arenot limited to, 100 ppm, 125 ppm, 150 ppm, 175 ppm and 200 ppm.

Suitable concentration ranges may vary depending on the specificantioxidant employed and the specific process used. Examples of suitableconcentration ranges include from about 1 ppm to about 200 ppm, fromabout 1 ppm to about 150 ppm, from about 1 ppm to about 100 ppm. Othersuitable concentration ranges would include from about 10 ppm to about200 ppm, from about 10 ppm to about 175 ppm, from about 10 ppm to about125 ppm, and from about 10 ppm to about 100 ppm. Other suitableconcentration ranges would include from about 25 ppm to about 200 ppm,from about 25 ppm to about 175 ppm, from about 25 ppm to about 125 ppm,and from about 25 ppm to about 100 ppm. Other suitable concentrationranges would include from about 50 ppm to about 200 ppm, from about 50ppm to about 175 ppm, from about 50 ppm to about 150 ppm, from about 50ppm to about 125 ppm, and from about 50 ppm to about 100 ppm.

The stabilized cyclic alkene composition can include a singleantioxidant of Formula (I) or a mixture of such antioxidants. Themixture of antioxidants may be in any relative proportion, and mayfurther include phenolic additives (e.g., a monohydroxybenzene)represented by Formula (II):

in which R⁵ through R⁹ can each independently be H, C₁-C₈ linear alkyl,C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈cyclic alkoxy or substituted or unsubstituted aryl. Examples of suitablesubstituents and preferred substituents are the same as previouslydescribed for Formula (I).

The cyclic alkenes can be obtained commercially or by synthetictechniques known to those in the art. In commercial materials, chemicalmanufacturers who make cyclic alkenes will often stabilize theirproducts with relatively high concentrations of BHT. Since mostmanufacturers are not accustomed to making high purity products, theirproduct handling techniques can be relatively poor, and air, moistureand other contaminants can possibly enter the container before, duringor after filling. These contaminants, once closed off into thecontainer, can cause considerable degradation to the product if it isstored for any length of time. For semiconductor purposes, thecommercial materials must be purified to remove all byproducts, andadditives, usually by distillation or sublimation.

However, to maintain purity and stabilization during purification,storage and shipping, the cyclic alkene and compositions of the presentdisclosure must be handled under strictly controlled conditions. Thesemay include: addition of a stabilizer to a product receiver prior todistillation so that a product is immediately stabilized once it entersthe product receiver, performing distillations under dry, inertatmospheres, rigorously cleaning and drying containers before use, usingclosed-filling techniques that prevent the product from being exposed toair, filling in a cleanroom to avoid dust and trace metal contaminationthat could act as polymerization catalysts, and carefully choosingcontainers to prevent exposure to air or other incompatible materials.

Stabilization of the cyclic alkene prior to purification is as importantas stabilization of the product during and after purification. While araw material selected for purification may already contain a stabilizersuch as BHT that was added by the manufacturer, it is common forstabilizer quality and concentration to degrade during storage. In thisinstance, it can be helpful to add an additional stabilizer or a mixtureof stabilizers to the raw material to consume impurities prior to andduring the purification process.

Since oxygen may be present in the raw material and in distillationequipment in some quantity, it may have the propensity to react withunstabilized cyclic alkene in the vapor phase during a distillation. Ifthis reaction were to occur and if the resulting impurity condensed in arefluxing process, the condensate may return to the distillation flask.There, it may combine with stabilizer and become deactivated before ithas the opportunity to cause residue formation. Following this samelogic, it is also important to immediately stabilize product that iscollected from the purification process so that any active impurity isdeactivated before it can begin to form residue.

An additional purification step may include a pretreatment filtrationthrough a polar medium such as silica gel or alumina in order to stripout impurities such as water, alcohols, peroxides, stabilizers,stabilizer degradation products, oxygenated organic impurities andparticulate matter. This step is ideally used to condition raw materialwhen charging a distillation flask. New, active stabilizer is added tothe raw material, or the raw material is charged onto stabilizer in theflask, to replace any that was lost during the filtration process.

While distillation of cyclic alkenes may be carried out successfully atatmospheric pressure with minimal degradation, the purification processmay be optimized for more sensitive cyclic alkenes by using alternativemethods. As distillation at a reduced pressure lowers the boiling pointof a cyclic alkene, those that are especially sensitive to heat canbenefit from distillation at a reduced pressure. Alternatively, the useof short-path distillation equipment, such as a wiped-film orfalling-film still, can reduce heated residence time and thereforereduce degradation that can lead to residue. Note that these methodsreduce the effectiveness of separating out impurities that have aboiling point similar to the target cyclic alkene. Therefore, they maybe used after an atmospheric distillation to strip out unwanted residualimpurities that may have formed in the initial purification process.

Alternative methods of stabilizing a cyclic alkene may include: adding astabilizer to a receiving vessel and running purified and unstabilizedcyclic alkene onto the stabilizer, flowing purified and unstabilizedcyclic alkene over a quantity of stabilizer as it passes to a receivingvessel in order to dissolve the stabilizer, and dosing stabilizer intopurified and unstabilized cyclic alkene that has been collected in areceiving vessel.

Since most appropriate stabilizers are solids, they can be moredifficult to manipulate and measure than liquids. Such stabilizers canbe dissolved in appropriate liquid solvents, or they may even bedissolved in high concentration in the target cyclic alkene. Analternative method of stabilizing cyclic alkenes also includesdissolving a solid stabilizer in an appropriate liquid solvent or in ahigh concentration in the cyclic alkene, whereby the resulting liquid isthen used to stabilize a cyclic alkene. Alternatively, several of thedescribed stabilizers can also be melted and handled as a liquid tostabilize a cyclic alkene.

The methods of purification and stabilization of cyclic alkenesdescribed above may be combined to ultimately provide a stabilizedproduct with the highest purity while avoiding the potential to formimpurities that can lead to residue.

Many chemical precursors and precursor compositions for thesemiconductor industry are typically packaged, shipped and stored instainless steel containers to retain product quality for the maximumamount of time. The product container is then connected to chemicaldelivery equipment that transfers the chemical by a precisely controlledmeans, to retain product and process purity and consistency. Such aprocess equipment is referred to here as a film deposition tool.

The compositions of the present disclosure may be used in any suitablechemical vapor deposition process which requires a cyclic alkene.Preferred processes are those chemical vapor deposition processesemploying a silicon containing compound to deposit a low dielectricconstant film. Examples of suitable processes include, but are notlimited to those described in U.S. Pat. Nos. 6,815,373, 6,596,627,6,756,323, 6,541,398, 6,479,110, 6,846,515, and 6,583,048, hereinincorporated by reference.

This disclosure is also directed to a process of using a cyclic alkenecomposition for forming a layer of carbon-doped silicon oxide on awafer. The process includes treating a cyclic alkene composition and asilicon containing compound in a film deposition chamber that contains asubstrate, thereby forming a carbon doped silicon oxide film on thesubstrate. The process can further include, prior to the treatment step,providing the cyclic alkene composition in a first container, thesilicon containing compound in a second container, a film depositiontool containing the film deposition chamber, a gas delivery line forconnecting the first and second containers to the film depositionchamber within the film deposition tool, and a stream of carrier gas tosweep the cyclic alkene composition and the silicon containing compoundthrough the gas delivery line into the film deposition chamber;introducing vapors of the cyclic alkene composition and the siliconcontaining compound into the carrier gas stream; and transporting thevapors of the cyclic alkene composition and silicon containing compoundinto the film deposition chamber via the carrier gas stream.

The cyclic alkenes suitable for the above-mentioned process can be thesame as described previously (vide supra).

Silicon containing compounds suitable for this disclosure includes anyclass of silicon containing molecule such as silanes, alkylsilanes,alkoxysilanes, alkylalkoxysilanes, carboxysilanes, alkylcarboxysilanes,alkoxycarboxysilanes, alkylalkoxycarboxysilanes, linear siloxanes,cyclic siloxanes, fluorinated silanes, fluorinated alkylsilanes,fluorinated alkoxysilanes, fluorinated alkylalkoxysilanes, fluorinatedcarboxysilanes, fluorinated alkylcarboxysilanes, fluorinatedalkoxycarboxysilanes, fluorinated alkylalkoxycarboxysilanes, fluorinatedlinear siloxanes, fluorinated cyclic siloxanes, and mixtures thereof.Examples of each class described above include, but are not limited to,those shown in Scheme 1 below. These silicon containing compounds mayalso be stabilized in a manner described by Teff et al. U.S. Pat. Nos.7,129,311 and 7,531,590 using compounds of Formula (I), Formula (II) ormixtures thereof described therein.

Suitable examples of silicon containing compounds of the presentdisclosure can also be those described by Formula (III):

In Formula (III), R¹⁰ through R¹³ can each independently be H, F, OH,C₁-C₈ linear alkyl, C₃-C₈ branched alkyl, C₂-C₈ unsaturated alkyl, C₁-C₈linear alkoxy, C₃-C₈ branched alkoxy, C₂-C₈ unsaturated alkoxy, C₄-C₈substituted cyclic alkyl or alkoxy, C₃-C₈ unsubstituted cyclic alkyl oralkoxy, substituted or unsubstituted aryl or aryl alkoxy, substitutedsilicon containing substituent, partially or fully fluorinated C₁-C₈linear alkyl, C₃-C₈ branched alkyl, C₂-C₈ unsaturated alkyl, partiallyor fully fluorinated C₁-C₈ linear alkoxy, C₃-C₈ branched alkoxy, C₂-C₈unsaturated alkoxy, partially or fully fluorinated C₄-C₈ substitutedcyclic alkyl or alkoxy, C₃-C₈ unsubstituted cyclic alkyl or alkoxy,partially or fully fluorinated substituted or unsubstituted aryl or arylalkoxy, partially or fully fluorinated substituted silicon containingsubstituent, non-, partially or fully fluorinated carboxylate ligands,or mixtures thereof. Examples of R¹⁰ through R¹³ in Formula (III)include, but are not limited to, H, F, OH, methyl, ethyl, propyl,iso-propyl, iso-propenyl, butyl, phenyl, methylphenyl, cyclohexyl,methylcyclohexyl, methoxy, ethoxy, propoxy, iso-propoxy, butoxy,phenoxy, methylphenoxy, cyclohexyloxy, methylcyclohexyloxy,trifluoromethyl, trifluoroethyl, penatafluoroethyl, trifluoropropyl,pentafluoropropyl, heptafluoropropyl, isopropyl, hexafluoroisopropyl,trifluoroisopropenyl, trifluorobutyl, pentafluorobutyl, nonafluorobutyl,trifluorophenyl, (trifluoromethyl)tetrafluorophenyl,undecafluorocyclohexyl, (trifluoromethyl)decafluorocyclohexyl,trifluoromethoxy, trifluoroethoxy, pentafluoroethoxy, trifluoropropoxy,pentafluoropropoxy, heptafluoropropoxy, hexafluoroisopropoxy,heptafluoroisopropoxy, trifluorobutoxy, pentafluorobutoxy,nonafluorobutoxy, pentafluorophenoxy,(trifluoromethyl)tetrafluorophenoxy, undecafluorocyclohexyloxy,(trifluoromethyl)decafluorocyclohexyloxy, dimethylsiloxy (in the case oflinear siloxanes), trimethylsiloxy, trimethyldisiloxy,pentamethyldisiloxy, diethylsiloxy, triethylsiloxy, triethyldisiloxy,pentaethyldisiloxy, dimethoxysiloxy, trimethoxysiloxy,trimethoxydisiloxy, pentamethoxydisiloxy, diethoxysiloxy,triethoxysiloxy, triethoxydisiloxy, pentaethoxydisiloxy,η²-trimethyltrisiloxy (in the case of cyclic siloxanes, such astetramethylcyclotetrasiloxane) and η²-hexamethyltrisiloxy (in the caseof cyclic siloxanes, such as octamethylcyclotetrasiloxane). Preferredexamples of R¹⁰ through R¹³ include H, F, methyl, methoxy, ethyl, ethoxyand siloxy. For Formula (III), H, methyl, ethoxy and substituted siloxyare most preferred for R¹⁰ through R¹³ for use in semiconductorapplications.

Examples of silicon containing compounds suitable for this disclosureinclude, but are not limited to, silane, methylsilane, dimethylsilane,trimethylsilane, tetramethylsilane, ethylsilane, diethylsilane,triethylsilane, tetraethylsilane, propylsilane, dipropylsilane,tripropylsilane, tetrapropylsilane, isopropylsilane, diisopropylsilane,triisopropylsilane, tetraisopropylsilane, butylsilane, dibutylsilane,tributylsilane, tetrabutylsilane, methyltrimethoxysilane,dimethyldimethoxysilane, trimethylmethoxysilane, trimethoxysilane,tetramethoxysilane, methylmethoxysilane, methyldimethoxysilane,methyltriethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane,tetraethoxysilane, methylethoxysilane, methyldiethoxysilane,methylpropoxysilane, dimethyldipropoxysilane, trimethylpropoxysilane,tetrapropoxysilane, methyltriisopropoxysilane,dimethyldiisopropoxysilane, trimethylisopropoxysilane,tetraisopropoxysilane, methyldiisopropoxysilane, methylphenylsilane,methyldiphenylsilane, methyltriphenylsilane, dimethyldiphenylsilane,trimethylphenylsilane, methyl(methylphenyl)silane,methyldi(methylphenyl)silane, methyltri(methylphenyl)silane,methylphenoxysilane, methyldiphenoxysilane, dimethyldiphenoxysilane,methyl(methylphenoxy)silane, methyldi(methylphenoxy)silane,dimethyldi(methylphenoxy)silane, methyl(cyclohexyl)silane,methyldi(cyclohexyl)silane, methyltri(cyclohexyl)silane,dimethyldi(cyclohexyl)silane, trimethyl(cyclohexyl)silane,methyl(methylcyclohexyl)silane, methyldi(methylcyclohexyl)silane,methyltri(methylcyclohexyl)silane, dimethyldi(methylcyclohexyl)silane,trimethyl(methylcyclohexyl)silane, methyl(cyclohexyloxy)silane,methyldi(cyclohexyloxy)silane, methyl(tricyclohexyloxy)silane,dimethyldi(cyclohexyloxy)silane, methyl(methylcyclohexyloxy)silane,methyldi(methylcyclohexyloxy)silane,methyltri(methylcyclohexyloxy)silane,dimethyldi(methylcyclohexyloxy)silane, silicon tetrafluoride,fluorotrimethylsilane, methyltris(trifluoromethoxy)silane,trifluoromethyltris(trifluoromethoxy)silane, fluorotriethoxysilane,triacetoxysilane, methoxytriacetoxysilane, vinyltriacetoxysilane,vinylmethyldiacetoxysilane, trimethylsilyl(trimethylsilyl)propynoate,trimethylsilyl(trimethylsiloxy)acetate, trimethylsilyltrifluoroacetate,tris(trifluoromethylsilyl)trifluoroacetate, triethylacetoxysilane,tri(trifluoroacetoxy)silane, methyltri(trifluoroacetoxy)silane,methoxytri(trifluoroacetoxy)silane, tetra(trifluoroacetoxy)silane,tetraacetoxysilane, phenyltriacetoxysilane, phenyldimethylacetoxysilane,phenyldimethoxyacetoxysilane, phenylacetoxytrimethylsilane,1,1,1,3,3-pentamethyl-3-acetoxydisiloxane,methyltriacetoxysilaneethyltriacetoxysilane, methyltriacetoxysilane,methacryloxytrimethylsilane, ethyltriacetoxysilane,dimethyldiacetoxysilane, di-t-butoxydiacetoxysilane,dibenzyloxydiacetoxysilane, bis(trimethylsilyl)malonate,bis(trimethylsilyl)acetylenedicarboxylate, acryloxytrimethylsilane,acetoxytrimethylsilane, acetoxymethyldimethylacetoxysilane,triethyl(trifluoroacetoxy)silane, phenyltri(trifluoroacetoxy)silane,phenyldi(trifluoromethyl)acetoxysilane,(pentafluorophenyl)dimethylacetoxysilane,phenyldimethyl(trifluoroacetoxy)silane,phenyl(trifluoroacetoxy)trimethylsilane,(trifluorophenyl)acetoxytrimethylsilane,phenylacetoxytri(trifluoromethyl)silane1,1,1,3,3-penta(trifluoromethyl)-3-acetoxydisiloxane,(trifluoromethyl)triacetoxysilaneethyltriacetoxysilane,(trifluoromethyl)triacetoxysilane,(trifluoromethyl)(trifluoromethoxy)diacetoxysilane,methacryloxytri(trifluoromethyl)silane,(trifluoroethyl)triacetoxysilane, di(trifluoromethyl)diacetoxysilane,di-(nonafluoro-t-butoxy)diacetoxysilane,dibenzyloxydi(trifluoroacetoxy)silane,acryloxytri(trifluoromethyl)silane, acetoxytri(trifluoromethyl)silane,acetoxy(trifluoromethyl)dimethylacetoxysilane, (trifluoromethyl)silane,di(trifluoromethyl)silane, tri(trifluoromethyl)silane,tetra(trifluoromethyl)silane, (trifluoroethyl)silane,di(trifluoroethyl)silane, tri(trifluoroethyl)silane,tetra(trifluoroethyl)silane, (trifluoropropyl)silane,di(trifluoropropyl)silane, tri(trifluoropropyl)silane,tetra(trifluoropropyl)silane, (hexafluoroisopropyl)silane,di(hexafluoroisopropyl)silane, tri(hexafluoroisopropyl)silane,tetra(hexafluoroisopropyl)silane, (trifluorobutyl)silane,di(trifluorobutyl)silane, tri(trifluorobutyl)silane,tetra(trifluorobutyl)silane, (trifluoromethyl)trimethoxysilane,di(trifluoromethyl)dimethoxysilane, tri(trifluoromethyl)methoxysilane,tetra(trifluoromethoxy)silane, (trifluoromethyl)methoxysilane,(trifluoromethyl)dimethoxysilane, (trifluoromethyl)triethoxysilane,di(trifluoromethyl)diethoxysilane, tri(trifluoromethyl)methoxysilane,tetra(trifluoroethoxy)silane, (trifluoromethyl)ethoxysilane,(trifluoromethyl)diethoxysilane, (trifluoromethyl)propoxysilane,di(trifluoromethyl)dipropoxysilane, tri(trifluoromethyl)propoxysilane,tetra(trifluoropropoxy)silane, (trifluoromethyl)triisopropoxysilane,di(trifluoromethyl)diisopropoxysilane,tri(trifluoromethyl)isopropoxysilane, tetra(trifluoroisopropoxy)silane,(trifluoromethyl)diisopropoxysilane, (trifluoromethyl)phenylsilane,(trifluoromethyl)diphenylsilane, (trifluoromethyl)triphenylsilane,di(trifluoromethyl)diphenylsilane, tri(trifluoromethyl)phenylsilane,(trifluoromethyl)(methylphenyl)silane,(trifluoromethyl)di(methylphenyl)silane,(trifluoromethyl)tri(methylphenyl)silane,(trifluoromethyl)phenoxysilane, (trifluoromethyl)diphenoxysilane,di(trifluoromethyl)diphenoxysilane,(trifluoromethyl)(methylphenoxy)silane,(trifluoromethyl)di(methylphenoxy)silane,di(trifluoromethyl)di(methylphenoxy)silane,(trifluoromethyl)(cyclohexyl)silane,(trifluoromethyl)di(cyclohexyl)silane,(trifluoromethyl)tri(cyclohexyl)silane,di(trifluoromethyl)di(cyclohexyl)silane,tri(trifluoromethyl)(cyclohexyl)silane,(trifluoromethyl)(methylcyclohexyl)silane,(trifluoromethyl)di(methylcyclohexyl)silane,(trifluoromethyl)tri(methylcyclohexyl)silane,di(trifluoromethyl)di(methylcyclohexyl)silane,tri(trifluoromethyl)(methylcyclohexyl)silane,(trifluoromethyl)(cyclohexyloxy)silane,(trifluoromethyl)di(cyclohexyloxy)silane,(trifluoromethyl)tri(cyclohexyloxy)silane,di(trifluoromethyl)di(cyclohexyloxy)silane,(trifluoromethyl)(methylcyclohexyloxy)silane,(trifluoromethyl)di(methylcyclohexyloxy)silane,(trifluoromethyl)tri(methylcyclohexyloxy)silane,di(trifluoromethyl)di(methylcyclohexyloxy)silane,tri(trifluoromethoxy)silane, methyltri(trifluoromethoxy)silane,dimethyldi(trifluoromethoxy)silane, trimethyl(trifluoromethoxy)silane,methyl(trifluormethoxy)silane, methyldi(trifluoromethoxy)silane,methyltri(trifluoroethoxy)silane, dimethyldi(trifluoroethoxy)silane,trimethyl(trifluoromethoxy)silane, methyl(trifluoroethoxy)silane,methyldi(trifluoroethoxy)silane, methyl(trifluoropropoxy)silane,dimethyldi(trifluoropropoxy)silane, trimethyl(trifluoropropoxy)silane,methyltri(hexafluoroisopropoxy)silane,dimethyldi(hexafluoroisopropoxy)silane,trimethyl(hexafluoroisopropoxy)silane,methyldi(hexafluoroisopropoxy)silane, methyl(pentafluorophenyl)silane,methyldi(pentaphenyl)silane, methyltri(pentaphenyl)silane,dimethyl(pentafluorophenyl)silane, trimethyl(pentafluorophenyl)silane,methyl[(trifluoromethyl)phenyl]silane,methyldi[(trifluoromethyl)phenyl]silane,methyltri[(trifluoromethyl)phenyl]silane,methyl(pentafluorophenoxy)silane, methyldi(pentafluorophenoxy)silane,dimethyldi(pentafluorophenoxy)silane,methyl[(trifluoromethyl)phenoxy]silane,methyldi[(trifluoromethyl)phenoxy]silane,dimethyldi[(trifluoromethyl)phenoxy]silane,methyl(undecafluorocyclohexyl)silane,methyldi(undecafluorocyclohexyl)silane,methyltri(undecafluorocyclohexyl)silane,dimethyldi(undecafluorocyclohexyl)silane,trimethyl(undecacyclohexyl)silane,methyl[(trifluoromethyl)cyclohexyl]silane,methyldi[(trifluoromethyl)cyclohexyl]silane,methyltri[(trifluoromethyl)cyclohexyl]silane,dimethyldi[(trifluoromethyl)cyclohexyl]silane,trimethyl[(trifluoromethyl)cyclohexyl]silane,methyl(undecafluorocyclohexyloxy)silane,methyldi(undecafluorocyclohexyloxy)silane,methyltri(undecafluorocyclohexyloxy)silane,dimethyldi(undecafluorocyclohexyloxy)silane,methyl[(trifluoromethyl)cyclohexyloxy]silane,methyldi[(trifluoromethyl)cyclohexyloxy]silane,methyltri[(trifluoromethyl)cyclohexyloxy]silane,dimethyldi[(trifluoromethyl)cyclohexyloxy]silane, hexamethyldisiloxane,octamethyltrisiloxane, octa(trifluoromethyl)trisiloxane,trimethyltrisiloxane, diethyltrimethyltrisiloxane,trimethylcyclotrisiloxane, tetramethylcyclotetrasiloxane,pentamethylcyclopentasiloxane, tetraethylcyclotetrasiloxane,pentaethylcyclopentasiloxane, hexamethylcyclotrisiloxane,octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,vinylmethyldiethoxysilane vinylmethyldimethoxysilane,trimethylsilylacetylene, di(trimethylsilyl)acetylene,hexa(trifluoromethyl)disiloxane, octa(trifluoromethyl)trisiloxane,tris(trifluoromethyl)trisiloxane, tris(trifluoromethyl)cyclotrisiloxane,tetra(trifluoromethyl)cyclotetrasiloxane,octa(trifluoromethyl)cyclotetrasiloxane and mixtures thereof.

Preferred examples of silicon containing compounds in Formula (III)include trimethylcyclotrisiloxane, triethylcyclotrisiloxane,tetramethylcyclotetrasiloxane, tetraethylcyclotetrasiloxane,pentamethylcyclopentasiloxane, pentaethylcyclopentasiloxane,octamethylcyclotetrasiloxane, methyltriethoxysilane,vinylmethyldimethoxysilane, vinylmethyldiethoxysilane,trimethylsilylacetylene, bis(trimethylsilyl)acetylene,methyldimethoxysilane and methyldiethoxsilane.Tetramethylcyclotetrasiloxane, methyldiethoxysilane,dimethyldimethoxysilane and trimethylsilylacetylene are most preferredfor use in the semiconductor industry.

In a typical chemical vapor deposition process requiring at least twoprecursors, there are several methods by which the components can becombined. Such a process is shown in FIGS. 1 and 2. For example, oneprecursor (e.g., a cyclic alkene) is transported from a container (1),through chemical delivery lines (2), to a vaporizer means (3) housed inthe film deposition tool (11). The precursor can be transported from thecontainer (1) through the delivery line (2) to the vaporizer means (3)by a variety of means, including, but not limited to, pressurization ofthe container with an inert gas, use of a mechanical pumping mechanism,gravity feed, or combinations thereof. The second precursor (e.g., asilicon containing compound) is transported from a separate container(12), through chemical delivery lines (13), to a vaporizer means (14)housed in the film deposition tool (11). The second precursor can betransported from the container (12) through the delivery line (13) tothe vaporizer means (14) by a variety of means, including, but notlimited to, pressurization of the container with an inert gas, use of amechanical pumping mechanism, gravity feed, or combinations thereof.

In the event that the second precursor (e.g., a silicon containingcompound) is a gas at room temperature, or it requires substantiallylittle or no energy to be vaporized as it is introduced into thechemical vapor process line (5), a second vaporizer means (14) may bereplaced by a valve, check valve, baffle, diffusing apparatus or similardevice meant to infuse gas into a tube or chamber without a means toenable vaporization.

It is important to note that, while it is desirable to have at least onevaporizer means (3) attached to a chemical vapor process line (5), it isalso possible to connect at least one vaporizer means (3) directly tothe deposition chamber (4), optionally connecting one or more additionalvaporizer means (14) to a chemical vapor process line (5) or directly tothe deposition chamber (4). Additionally, a gas delivery line (8) mayoptionally be connected directly to the deposition chamber (4). In theevent that no vaporizer means (3, 14) or gas delivery lines (8) areconnected to a chemical vapor process line (5), the chemical vaporprocess line becomes a feature that is optionally attached to thedeposition chamber (4).

Ideally, separate chemical delivery lines and vaporizer means are usedfor each precursor. However, it is possible for two precursors to bevaporized using a single vaporizer means when the two precursors arechemically compatible. When using a single vaporizer means (3), bothprecursors are combined or separately dispensed through a portion of thechemical delivery line (15) to the vaporizer means (3). When the twoprecursors are combined prior to vaporization, as shown in FIG. 2, theprocess simply involves their combination in the chemical delivery line(15), followed by vaporization of the two precursors in the vaporizermeans (3). When the two precursors are separately dispensed through asingle vaporizer means (3), the sequence to dispense each precursorcould simply involve flow of one precursor through the chemical deliveryline (15) to the vaporizer means (3) followed by flow of a secondprecursor through the chemical delivery line (15) to the vaporizer means(3) without repetition. Alternatively, there may be a need to flow oneprecursor, flow the second precursor, and repeat these steps until thedesired layer is formed. The process used is wholly dependent on thefilm properties desired. In the event that only one vaporizer means (3)is used, the second vaporizer means (14) is not needed.

In a process of flowing two different precursors through separatechemical lines and vaporizer means, a suitable precursor flow rate foreach precursor can range from about 0.01 to about 10 mL/minute. Thevaporizer means (3, 14) serves as a means to convert liquid precursor toa vapor or mist, and it can use various techniques, such as heat, highpressure gas, or other means to accomplish this task. Alternatively, thevaporizer means (3, 14) may consist of a container that holds a volumeof liquid, through which an inert gas is flowed as a means to (a)convert the precursor from a liquid to a vapor, and (b) transport theprecursor vapor into the chemical vapor process line (5). Regardless ofthe vaporizer means (3, 14) design, the conversion of the precursor fromliquid to gaseous state may take place either in the vaporizer means (3,14) or in the chemical vapor process line (5). The precursor is injectedin the form of a vapor or mist into the chemical vapor process line (5)that is commonly heated between about 30° C. and about 120° C. toprevent the precursor vapor from condensing inside the line (5). Mixingof the precursor components can take place in the chemical vapor processline (5), or in different locations within the deposition chamber (4),depending on where the vaporizer means (3, 14) are located with respectto one another. The chemical vapor process line (5) is connected to thedeposition chamber (4) inside the film deposition tool (11), andsubstrate (6) is housed within the deposition chamber (4). Thedeposition chamber (4) and chemical vapor process line (5) may beoperated at ambient pressure (i.e., 760 torr), but it is also common tooperate below atmospheric pressure, from about 0.01 torr to about 700torr, to enhance vaporization of the precursors and to help keep theprecursors in the vapor phase.

It should be understood by those skilled in the art that the connectionbetween the chemical vapor process line (5) and the deposition processchamber (4) can vary from deposition tool to deposition tool, dependingon the requirements for the process. For example, designs may includevarious apparatuses that affect the mixing, heating, cooling, ordistribution of gases within the system. These may include an apparatushaving baffles to mix the gases, a heated zone to heat gases, a coolingzone to cool gases, a chamber to allow pressure equilibration, or ashowerhead to distribute gases over the surface of a wafer. Designs may,for example, route chemical vapors from the chemical vapor process line(5) through a baffled mixing apparatus, through a heated zone andthrough a showerhead before the gases are passed to the substrate (6) inthe deposition chamber (4). Due to the complexity of designs that areavailable in the market and their variability based on need driven bythe process, the options are described only in general terms here.

In our general example, the precursor vapors are transported through thechemical vapor process line (5) to the substrate (6) in the depositionchamber (4) by a stream of gas flowing past the vaporizer means (3, 14).The stream of gas is supplied from a source tank (7) and flows through agas delivery line (8) to the chemical vapor process line (5). The streamof gas, having a flow rate of about 5 sccm to about 10,000 sccm, isoften heated to enhance vaporization of the precursors to help keep theprecursors in the vapor phase. The gas used may be inert, such asnitrogen, helium or argon, chosen simply to act as a means to transportthe precursor vapor to the substrate, or it may be a reactive gas, suchas oxygen, ozone, ammonia, nitrous oxide, carbon dioxide, carbonmonoxide, SiH₄, silanes, silicon tetrafluoride, hydrazine and the liketo enhance the deposition process.

As the precursor vapors are transported to the substrate (6), they maybe mixed with one or more reactants, in addition to the transport gas,to enhance its deposition onto the substrate. The reactants may bereactive gases as mentioned above, or they may be other chemicalprecursors such as amines, aminoalcohols, alkanes, alkenes, alkynes,alcohols, esters, ketones, aldehydes, carboxylic acids and the like. Thereactants are carefully selected to enhance the deposition of precursoron the substrate, and to modify the chemical identity and properties ofthe layer deposited onto the substrate. These reactants can beintroduced into the film deposition tool (11) by various means and atvarious locations in the process, depending on the desired effect. It ismost convenient to introduce a reactant into the film deposition tool(11) in gaseous form, so it would be necessary to have an additionalvaporizer means in the case where liquid reactants are used. Anadditional vaporizer means, or gas delivery line used to introduce areactant can be placed near the point where the gas delivery line (8)meets the chemical vapor process line (5), upstream or downstream of thevaporizer means, directly into or near the plasma (9), and/or somewhereon the sides, top, or bottom of the film deposition chamber (4) of thefilm deposition tool (11).

The precursor vapors, potential reactants, and inert or reactive gasesmay also experience other conditions used to enhance deposition, such asheat or plasma (9). The precursor vapor may be preheated to betweenabout 50° C. and about 800° C. before contact with the substrate toenhance the deposition of the precursors on the substrate. A plasma mayalso be used to add energy to the precursor vapors and enhance thedeposition. Additionally, the plasma may be pulsed on and off to changethe properties of the deposited film. The plasma power and pulseduration are carefully selected to enhance the deposition of theprecursors on the substrate, and to modify the chemical identity andproperties of the layer deposited onto the substrate. The plasma mayalso be applied over a range of frequencies, where the high and lowfrequency plasma power may range from about 0 to several kilowatts. Thesubstrate may also have a bias of between about 0 and about −400 VDC toenhance material transport to the substrate. The substrate may be heatedfrom about 25° C. to about 500° C. to either cause thermal breakdown ofthe precursor on the substrate, or may be used to enhance the depositionof precursor on the substrate. Unreacted materials are exhausted throughan exhaust line (10).

The elemental composition of the film, and thus the film properties, canbe adjusted by the choice of starting silicon containing compound, thecyclic alkene employed, and the use or lack of use of various reactivegases in the process.

Subsequent to the film deposition, the initial film may be subjected toa curing step. The curing steps may also be employed to modify e.g., thedensity or elemental compositions of the films to change film propertiessuch as film strength, dielectric constant and various other propertiesof the film. These curing steps may include a thermal treatment by theapplication of heat through one of various heating means such as hotplates, ovens, infrared lamps, or microwaves. Alternatively, the curingmay include a plasma treatment, or a chemical treatment of the film.These curing steps may take place in an inert atmosphere (e.g., noblegases), a reducing atmosphere (e.g., hydrogen or hydrocarbon), or anoxidizing atmosphere (e.g., oxygen, air, ozone, nitrous oxide, carbondioxide) depending on the desired chemical change in the initial film.Such processes are known to those skilled in the art.

EXAMPLES

A series of tests were devised to compare the propensity for stabilizedand unstabilized NBDE samples to form soluble, nonvolatile polymericresidue under various stress conditions. In these tests, samples wereprepared by carefully distilling NBDE under nitrogen using similarconditions. For stabilized samples, NBDE was distilled under nitrogendirectly onto each stabilizer. After the samples were prepared, theywere transferred into 250 mL glass bulb test containers that were fittedwith a Kontes valve and Schlenk line adapter. This container was idealfor testing since it could be resealed, was compatible with Schlenktechniques, and the only wetted parts were glass or Teflon. The sampleswere carefully handled under nitrogen to prevent exposure toadventitious gases before the experiment. Some samples were degassedusing three freeze-pump-thaw cycles to remove dissolved gases. Somesamples were exposed to oxygen, where the amount of oxygen was carefullyintroduced using calculated amounts of air. All heated samples wereheated in a controlled temperature oil bath for a specific length oftime. After each experiment was completed, the amount of nonvolatile,polymeric residue was determined using an evaporative technique thatseparated the volatile portion (NBDE and stabilizer) from thenonvolatile portion (polymeric residue). The evaporative techniquesimultaneously evaporated NBDE and stabilizer from a preweighed samplepan inside a container fitted with a nitrogen inlet and a vapor outlet.Nitrogen flow and heating at 80° C. facilitated the evaporation process,and residue was determined by the difference in the weight of the samplepan before and after the test. The amount of residue was reported asparts per million (ppm) by weight after comparing the mass of thenonvolatile portion to the total weight of the sample, and the detectionlimit was approximately 0.5 ppm. Lower residue values after testing arean indication of greater stability.

Example 1

This test was chosen to demonstrate how NBDE performs when exposed toheat for a period of time. As mentioned previously, NBDE may be exposedto elevated temperatures up to 80° C. for hours or days, so the productmust demonstrate resistance to thermal degradation under suchconditions.

Additionally, this test can give an initial indication of product shelflife. Accelerated aging tests commonly assume that chemical reactionsfollow the Arrhenius reaction rate function. Generally, this states thatdegradation rates increase 2× with every 10° C. increase in temperature.Therefore, a heating test at 80° C. for 8.1 days is approximately equalto a sample stored at 25° C. for 365 days. For the above test, 80° C.for 12 hours is approximately equal to a sample stored at 25° C. for 3weeks.

The stabilizers tested were MHQ and 4-MCAT, and each was tested at twodifferent concentrations to determine if a higher concentration was moreeffective. The initial residue concentration for each sample wasmeasured to determine the baseline prior to heating. The baselines were31 ppm for unstabilized NBDE (Sample 1), lower than 2 ppm for Samples2-3, and lower than 0.5 ppm for Samples 4-5. Since all distillationswere done under the same conditions, this could be an indication of thedifficulty of isolating high purity NBDE in the absence of a stabilizer.Once the baseline was established, sample bulbs were carefully filled inthe absence of air and subsequently degassed as described above. Thesamples were heated at 80° C. for 12 hours and then tested for residueconcentration. The test results are summarized in Table 1 below.

TABLE 1 Stability Tests of Degassed NBDE at 80° C. Sample Time (hr) T (°C.) Reactive Gas Stabilizer Type Residue (ppm) 1 12 80 Degassed None N/A227 2 12 80 Degassed 50 ppm MHQ Monohydroxy 122 3 12 80 Degassed 100 ppmMHQ Monohydroxy 83 4 12 80 Degassed 50 ppm 4-MCAT Dihydroxy <0.5 5 12 80Degassed 100 ppm 4-MCAT Dihydroxy <0.5

Results in Table 1 show that the unstabilized sample formed a fairamount of residue. Comparing the monohydroxybenzene stabilized samplesto unstabilized material, MHQ showed a reduction in residue. The higherconcentration of MHQ gave a lower residue concentration. However, thedihydroxybenzene stabilized samples both unexpectedly showed improvedperformance over each of the monohydroxybenzene stabilized samples, withexcellent results at either concentration.

Example 2

This test was chosen to demonstrate how NBDE performs when exposed toboth heat and oxygen for certain lengths of time. The oxygenconcentration used for this test was 25 ppm by weight. Thisconcentration is similar to what one would expect from an accidentalexposure of chemical to air during packaging, though it is a relativelylarge exposure considering the lengths usually taken by chemicalmanufacturers to avoid oxygen contamination when preparing semiconductorgrade products.

The stabilizers tested were MHQ and 4-MCAT, and each was tested at twodifferent concentrations to determine if a higher concentration was moreeffective. The initial residue concentration for each sample wasmeasured to determine the baseline prior to heating. The baselines were31 ppm for unstabilized NBDE (Sample 6), lower than 2 ppm for Samples7-8 were, and lower than 0.5 ppm for Samples 9-10. Once the baseline wasestablished, sample bulbs were filled in the presence of a knownquantity of air to give 25 ppm of oxygen by weight of the sample. Thesamples were heated at 80° C. for 12 hours and then tested for residueconcentration. The results are summarized in Table 2 below.

TABLE 2 Stability Tests of NBDE with 25 ppm O₂ at 80° C. Sample Time(hr) T (° C.) Reactive Gas Stabilizer Type Residue (ppm) 6 12 80 25 ppmO₂ None N/A 1588 7 12 80 25 ppm O₂ 50 ppm MHQ Monohydroxy 836 8 12 80 25ppm O₂ 100 ppm MHQ Monohydroxy 576 9 12 80 25 ppm O₂ 50 ppm 4-MCATDihydroxy 3 10 12 80 25 ppm O₂ 100 ppm 4-MCAT Dihydroxy <0.5

Results in Table 2 show that the unstabilized sample formed asignificant amount of residue. Comparing the monohydroxy stabilizedsamples to unstabilized material, MHQ showed a reduction in residue. Thehigher concentration of MHQ gave a lower residue concentration. However,the dihydroxybenzene stabilized samples both unexpectedly showedimproved performance over each of the monohydroxybenzene stabilizedsamples. Though there were excellent results at either concentration,the higher stabilizer concentration showed better performance.

Example 3

This test was chosen as an extreme condition to stress the product andhelp sort out the effectiveness of different stabilizers. Oxygen wasadded at 150 ppm by weight as a way to stress the product anddemonstrate clear differences between more and less effectivestabilizers.

The stabilizers tested are as follows: 4-methoxyphenol (MHQ),2,6-di-tert-butyl-4-methylphenol (BHT),2,6-di-tert-butyl-4-methoxyphenol (BHA), 3-methoxy-1,2-dihydroxybenzene(3-MOCAT), 4-methyl-1,2-dihydroxybenzene (4-MCAT) and1,2-dihydroxybenzene (pyrocatechol). The first three stabilizers have asingle OH substituent (monohydroxy) while the last three have two OHsubstituents (dihydroxy). The initial residue concentration for eachsample was measured to determine the baseline prior to heating. Thebaselines were 31 ppm for unstabilized NBDE (Sample 11) and lower than 2ppm for Samples 12-17. Once the baseline was established, sample bulbswere filled in the presence of a known quantity of air to give 150 ppmof oxygen by weight of the sample. The samples were heated at 80° C. for12 hours and then tested for residue concentration. The results aresummarized in Table 3.

TABLE 3 Stability Tests of NBDE with 150 ppm O₂ at 80° C. Sample Time(hr) T (° C.) Reactive Gas Stabilizer Type Residue (ppm) 11 12 80 150ppm O₂ None N/A 10487 12 12 80 150 ppm O₂ 150 ppm MHQ Monohydroxy 180013 12 80 150 ppm O₂ 150 ppm BHT + 50 ppm MHQ Monohydroxy 45 14 12 80 150ppm O₂ 150 ppm BHA + 50 ppm MHQ Monohydroxy 38 15 12 80 150 ppm O₂ 150ppm 3-MOCAT Dihydroxy 16 16 12 80 150 ppm O₂ 150 ppm 4-MCAT Dihydroxy 1117 12 80 150 ppm O₂ 150 ppm pyrocatechol Dihydroxy 7

Results in Table 3 show that the unstabilized sample formed asignificant amount of residue compared to all of the stabilized samples.This result was notably higher than tests performed in Examples 1 and 2which used milder conditions. Samples 13 and 14 were prepared to probethe effectiveness of stabilizer mixtures. Comparing themonohydroxybenzene stabilized samples to unstabilized material, MHQshowed a marked reduction in residue but the MHQ mixtures with BHT orBHA both performed better. However, the dihydroxybenzene stabilizedsamples showed improved performance over each of the monohydroxybenzenestabilized samples at an equivalent or lower concentration.

Example 4

This test was chosen to demonstrate how a product would perform whenexposed to a greater heat extreme for a period of time. Although NBDE isnot expected to experience temperatures of 120° C. for 24 hours, is testcan demonstrate if this extreme temperature adversely affects theproduct. It may also give an initial indication of shelf life where 24hours at 120° C. is approximately equal to 2 years at 25° C.

The stabilizers tested were MHQ and 4-MCAT, and each was tested at twodifferent concentrations to determine if a higher concentration was moreeffective. The initial residue concentration for each sample wasmeasured to determine the baseline prior to heating. The baseline was 31ppm for unstabilized NBDE (Sample 18), lower than 2 ppm for Samples19-20, and lower than 0.5 ppm for Samples 21-22. Once the baseline wasestablished, sample bulbs were carefully filled in the absence of airand subsequently degassed as described above. The samples were heated at120° C. for 24 hours and then tested for residue concentration. Theresults are summarized in Table 4.

TABLE 4 Stability Tests of NBDE without O₂ at 120° C. Sample Time (hr) T(° C.) Reactive Gas Stabilizer Type Residue (ppm) 18 24 120 DegassedNone N/A 1862 19 24 120 Degassed 50 ppm MHQ Monohydroxy 822 20 24 120Degassed 100 ppm MHQ Monohydroxy 331 21 24 120 Degassed 50 ppm 4-MCATDihydroxy 157 22 24 120 Degassed 100 ppm 4-MCAT Dihydroxy 157

Results in Table 4 show that the unstabilized sample formed significantresidue. While the amount of residue formed was greater than that seenat 80° C. when degassed (see Table 1), not as much residue was formedcompared to that formed when the unstabilized sample was exposed to bothheat and oxygen (see Table 3). Comparing the monohydroxybenzenestabilized samples to unstabilized material, MHQ showed a reduction inresidue. Further, the higher concentration of MHQ gave a lower residueconcentration. However, the dihydroxybenzene stabilized samples bothunexpectedly showed improved performance over each of themonohydroxybenzene stabilized samples at either concentration, even atthis extreme temperature.

It is important to note that all samples of this Example showed evidenceof thermal degradation as detected by gas chromatography-massspectrometry (GC-MS) and the resulting residue had a differentappearance. Residue formed in the presence of oxygen gave colorless orwhite yellow solid (often a “bubbly” mass) while residue formed at 120°C. gave a tan colored solid with the appearance of melted caramel. Sincea phenolic stabilizer may not necessarily be effective against thermaldegradation (e.g., due to a Diels-Alder 2+2 addition), this test may notbe a reliable way to gauge the effectiveness of such stabilizers. Sincethere appear to be two active modes of degradation at 120° C., it is notpossible to rely on the Arrhenius model to predict shelf life testing atthis temperature.

Example 5

The cyclic alkene, NBDE, stabilized with 100 ppm of 4-MCAT or 3-MOCAT istransferred, with the aid of helium pressure, from a stainless steelcontainer through a chemical delivery line to a heated vaporizer at aflow rate of 1 mL/min. The cyclic alkene is vaporized into a chemicalvapor process line that is heated to 80° C. and transported to asubstrate using 500 sccm of helium as a transport gas with the systembase pressure held at 6 torr. During transport to the substrate, thecyclic alkene vapor and transport gas is mixed with a flow ofmethyldiethoxysilane (M-DEOS) in a proportion of approximately 60% byweight M-DEOS and 40% by weight NBDE. This gas mixture is exposed to aplasma power of 250 W. The substrate is heated to 150° C. with asubstrate bias of −15 VDC. A carbon doped silicon oxide film isdeposited on the substrate using these conditions.

Example 6

The cyclic alkene, NBDE, stabilized with 100 ppm of 4-MCAT or 3-MOCAT istransferred, with the aid of helium pressure, from a stainless steelcontainer through a chemical delivery line to a heated vaporizer at aflow rate of 1 mL/min. The cyclic alkene is vaporized into a chemicalvapor process line that is heated to 80° C. and transported to asubstrate using 500 sccm of helium as a transport gas with the systembase pressure held at 6 torr. During transport to the substrate, thecyclic alkene vapor and transport gas is mixed with a flow of TMCTS in aproportion of approximately 60% TMCTS and 40% NBDE. This gas mixture isexposed to a plasma power of 250 W. The substrate is heated to 150° C.with a substrate bias of −15 VDC. A carbon doped silicon oxide film isdeposited on the substrate using these conditions.

Example 7

This example employs the process in Example 5, however the carbon dopedsilicon oxide film is treated by a post-deposition curing step. The filmis annealed at 425° C. under nitrogen for 4 hours to removesubstantially all of the NBDE porogen that remains in the film. Thistreatment typically gives a slightly thinner film with a lowerdielectric constant.

Example 8

This example employs the process in Example 6, however the carbon dopedsilicon oxide film is treated by a post-deposition curing step. The filmis annealed at 425° C. under nitrogen for 4 hours to removesubstantially all of the NBDE porogen that remains in the film. Thistreatment typically gives a slightly thinner film with a lowerdielectric constant.

Example 9

This example employs the process in Example 5, however the cyclicalkene, NBDE, is stabilized with 50 ppm of 4-MCAT and 50 ppm of 3-MOCAT.A carbon doped silicon oxide film is deposited on the substrate.

Example 10

This example employs the process in Example 5, however the cyclicalkene, NBDE, is stabilized with 50 ppm of 4-MCAT and 50 ppm of BHT. Acarbon doped silicon oxide film is deposited on the substrate.

Example 11

This example employs the process in Example 7, however the cyclicalkene, NBDE, is stabilized with 100 ppm of3-isopropyl-1,2-dihydroxybenzene. A carbon doped silicon oxide film isdeposited on the substrate.

Example 12

This example employs the process in Example 5, however the cyclicalkene, a 75:25 by weight mixture of NBDE and alpha-terpinene, isstabilized with 100 ppm of 3-isopropyl-1,2-dihydroxybenzene. A carbondoped silicon oxide film is deposited on the substrate.

Example 13

This example employs the process in Example 5, however the cyclicalkene, a 25:75 by weight mixture of dicyclopendtadiene:alpha-terpinene,is stabilized with 100 ppm of 3-isopropyl-1,2-dihydroxybenzene. A carbondoped silicon oxide film is deposited on the substrate.

Example 14

This example employs the process in Example 8, however the cyclicalkene, NBDE, is stabilized with 200 ppm of3-tert-butyl-4-methyl-1,2-dihydroxybenzene. A carbon doped silicon oxidefilm is deposited on the substrate.

Example 15

This example employs the process in Example 6, however the cyclicalkene, NBDE, is stabilized with 50 ppm of 4-MCAT. A carbon dopedsilicon oxide film is deposited on the substrate.

Example 16

This example employs the process in Example 7, however the cyclicalkene, NBDE, is stabilized with 150 ppm of 4-MCAT. A carbon dopedsilicon oxide film is deposited on the substrate.

Example 17

This example employs the process in Example 8, however the cyclicalkene, alpha-terpinene, is stabilized with 100 ppm of 4-MCAT. A carbondoped silicon oxide film is deposited on the substrate.

Example 18

This example employs the process in Example 5, however the cyclicalkene, limonene, is stabilized with 100 ppm of 4-MCAT. A carbon dopedsilicon oxide film is deposited on the substrate.

Example 19

This example employs the process in Example 5, however the cyclicalkene, alpha-pinene, is stabilized with 200 ppm of 4-MOCAT. A carbondoped silicon oxide film is deposited on the substrate.

Example 20

This example employs the process in Example 5, however the cyclicalkene, dicyclopentadiene, is stabilized with 150 ppm of 4-MCAT. Acarbon doped silicon oxide film is deposited on the substrate.

Example 21

This example employs the process in Example 5, however the cyclicalkene, 1,4-dihydro-1,4-methanonaphthalene, is stabilized with 100 ppmof 3,4-dimethyl-1,2-dihydroxybenzene. A carbon doped silicon oxide filmis deposited on the substrate.

Example 22

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of methyldiethoxysilane(M-DEOS) and a flow of tetramethyldisiloxane (TMDSO) in a proportion ofapproximately 40% by weight M-DEOS, 20% by weight TMDSO and 40% byweight NBDE. A carbon doped silicon oxide film is deposited on thesubstrate.

Example 23

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of methyldiethoxysilane(M-DEOS) and a flow of tetramethyldisiloxane (TMDSO) in a proportion ofapproximately 30% by weight M-DEOS, 30% by weight TMDSO and 40% byweight NBDE. A carbon doped silicon oxide film is deposited on thesubstrate.

Example 24

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of trimethylsilane (TMS) ina proportion of approximately 60% by weight TMS and 40% by weight NBDE.A carbon doped silicon oxide film is deposited on the substrate.

Example 25

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of fluorotriethoxysilane(FTES) in a proportion of approximately 60% by weight FTES and 40% byweight NBDE. A carbon doped silicon oxide film is deposited on thesubstrate.

Example 26

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of acryloxytrimethylsilane(AcroTMS) in a proportion of approximately 60% by weight AcroTMS and 40%by weight NBDE. A carbon doped silicon oxide film is deposited on thesubstrate.

Example 27

This example employs the process in Example 5, however the cyclic alkenevapor and transport gas is mixed with a flow of acetoxytrimethylsilane(AceTMS) in a proportion of approximately 60% by weight AceTMS and 40%by weight NBDE. A carbon doped silicon oxide film is deposited on thesubstrate.

A series of tests were devised to examine product shelf life undernormal storage conditions over a one year timeframe. This is a keymeasure of long term stabilizer performance. Eight high purity stainlesssteel containers were filled in essentially the same manner fromstandard high volume production lots. Initial purity with respect toresidue concentration was found to be nearly identical. The containerswere sealed and were stored at approximately 25° C. (“room temperature”)in an inert atmosphere under atmospheric pressure. Residue concentrationwas measured at the time of fill as a sample baseline, and then sampleswere pulled over the course of approximately one year in order tomeasure the increase in residue concentration. Residue concentration wasmeasured as described in the above examples. The results are shown inFIGS. 3-5.

Example 28

FIG. 3 shows the residue concentration of four samples of NBDEstabilized with 50 ppm of MHQ as a function of sample age. Trend lineswere used to highlight the highest and lowest concentration trends seenin the four samples. Based on these results, residue formation over timewas approximately linear. Although the variation of the rate of residueformation between these samples was relatively large and not clearlyunderstood, it was believed that small differences in oxygenconcentration due to packaging and sampling may play a role. Using thisdata, one may reasonably predict that residue formed in a sample overthe course of one year under similar storage conditions would vary fromabout 70 to about 190 ppm.

Example 29

FIG. 4 shows the residue concentration of four samples of NBDEstabilized with 100 ppm of 4-MCAT as a function of sample age. Trendlines again were used to highlight the highest and lowest concentrationtrends seen in the four samples. As seen with MHQ stabilized product,residue formation over time was approximately linear. However, residueconcentration in the 4-MCAT stabilized samples under similar conditionswas lower by at least an order of magnitude. In this case, the predictedresidue after one year would vary from about 4 to about 6 ppm. Not onlywas the overall residue concentration lower, it was also more tightlydistributed and therefore more predictable.

Example 30

The dramatic difference between the long term behavior of the MHQ and4-MCAT stabilized products is most obvious when both studies are plottedon the same graph, as seen in FIG. 5. This figure clearly shows thedifferences both in range and in overall residue concentration formedover the same period.

General Purification Procedure #1

Cyclic alkene is purified by passing it through a filtration device thatis charged with silica gel or alumina media in a manner to removeimpurities such as water, alcohols, peroxides, stabilizers, stabilizerdegradation products, oxygenated organic impurities and particulatematter.

General Purification Procedure #2

Cyclic alkene is charged into a distillation flask fitted with adistillation column, a condenser and two receiving vessels. Onereceiving vessel is designated for forerun, or more volatile fraction,and one receiving vessel is designated for collecting the main fraction,or high purity cyclic alkene. The distillation is operated under inertatmosphere at atmospheric pressure. A sufficient forerun fraction iscollected to remove more volatile impurities, a main fraction iscollected to separate out high purity cyclic alkene of desired purity,and the distillation process is terminated to leave behind a heelfraction of less volatile impurities.

General Purification Procedure #3

Cyclic alkene is charged into a distillation flask fitted with adistillation column, a condenser, two receiving vessels and a vacuumsource. One receiving vessel is designated for forerun, or more volatilefraction, and one receiving vessel is designated for collecting the mainfraction, or high purity cyclic alkene. The distillation is operatedunder inert atmosphere below atmospheric pressure to reduce the boilingpoint of the cyclic alkene to reduce or prevent thermal degradationduring the distillation step. A sufficient forerun fraction is collectedto remove more volatile impurities, a main fraction is collected toseparate out high purity cyclic alkene of desired purity, and thedistillation process is terminated to leave behind a heel fraction ofless volatile impurities.

General Purification Procedure #4

Cyclic alkene is charged into a short path distillation system fittedwith a heated zone, a condenser and two receiving vessels. One receivingvessel is designated for collecting the main fraction, or high puritycyclic alkene, and one receiving vessel is designated for receiving lessvolatile impurities. The distillation is operated under inert atmosphereat atmospheric pressure and is tuned to offer sufficient separation ofhigh purity cyclic alkene from less volatile impurities.

General Purification Procedure #5

Cyclic alkene is charged into a short path distillation system fittedwith a heated zone, a condenser and two receiving vessels. One receivingvessel is designated for collecting the main fraction, or high puritycyclic alkene, and one receiving vessel is designated for receiving lessvolatile impurities. The distillation is operated under inert atmospherebelow atmospheric pressure to reduce the boiling point of the cyclicalkene to reduce or prevent thermal degradation during the distillationstep. Further, the process is tuned to offer sufficient separation ofhigh purity cyclic alkene from less volatile impurities.

General Stabilization Procedures General Stabilization Procedure #1

An effective amount of stabilizer is charged into a product receivingvessel of a distillation system prior to distilling a high purity cyclicalkene into the receiving vessel. The distillation system is thenoperated to have the high purity cyclic alkene contact and solubilizethe stabilizer as it is collected in the receiving vessel.

General Stabilization Procedure #2

An effective amount of a stabilizer is charged into a distillationsystem at a point between the condenser and product receiving vessel.The distillation system is then operated to have a high purity cyclicalkene contact and solubilize the stabilizer as it passes from thecondenser to the receiving vessel.

General Stabilization Procedure #3

A distillation system is first operated to collect unstabilized highpurity cyclic alkene in a receiving vessel without containing astabilizer. An effective amount of the stabilizer is then charged intothe receiving vessel in order to solubilize the stabilizer in the highpurity cyclic alkene.

Example 31

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #2 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #1.

Example 32

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #3 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #1.

Example 33

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #4 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #1.

Example 34

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #5 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #1.

Example 35

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #1 followed by General Purification Procedure #2 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 36

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #1 followed by General Purification Procedure #3 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 37

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #1 followed by General Purification Procedure #4 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 38

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #1 followed by General Purification Procedure #5 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 38

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #2 followed by General Purification Procedure #4 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 38

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #3 followed by General Purification Procedure #5 andstabilized with 100 ppm of 4-MCAT by employing General StabilizationProcedure #1.

Example 39

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #1 followed by General Purification Procedure #2 followed byGeneral Purification Procedure #4 and stabilized with 100 ppm of 4-MCATby employing General Stabilization Procedure #1.

Example 40

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #2 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #2.

Example 41

The cyclic alkene, NBDE, is purified by employing General PurificationProcedure #2 and stabilized with 100 ppm of 4-MCAT by employing GeneralStabilization Procedure #3.

While we have shown and described several embodiments in accordance withthe present disclosure, it is to be clearly understood that the same aresusceptible to numerous changes apparent to one skilled in the art.Therefore, we do not wish to be limited to the details shown anddescribed but intend to show all changes and modifications which comewithin the scope of the appended claims.

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety.

1. A composition, comprising: (a) at least one substituted or unsubstituted cyclic alkene, and (b) an antioxidant composition comprising at least one compound of Formula (I),

wherein R¹ through R⁴ each independently is H, C₁-C₈ linear alkyl, C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈ linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈ cyclic alkoxy or substituted or unsubstituted aryl, provided that at least one of R¹ through R⁴ is not H, or if one of R¹ through R⁴ is t-butyl, at least one of the remaining R¹ through R⁴ is not H.
 2. The composition of claim 1, wherein one of R¹ through R⁴ is methyl, ethyl, methoxy, or ethoxy.
 3. The composition of claim 2, wherein at least one of the remaining R¹ through R⁴ is H.
 4. The composition of claim 2, wherein all of the remaining R¹ through R⁴ are H.
 5. The composition of claim 1, wherein R² or R³ is methyl or methoxy.
 6. The composition of claim 5, wherein at least one of the remaining R¹ through R⁴ are H.
 7. The composition of claim 1, wherein the antioxidant composition comprises 4-methyl-1,2-dihydroxybenzene.
 8. The composition of claim 1, wherein the antioxidant composition comprises 3-methoxy-1,2-dihydroxybenzene.
 9. The composition of claim 1, wherein the antioxidant composition is present in a concentration between about 1 ppm and about 200 ppm.
 10. The composition of claim 1, wherein the antioxidant composition is present in a concentration between about 50 ppm and about 150 ppm.
 11. The composition of claim 1, wherein the composition comprises a cyclic alkene having the general formula C_(n)H_(2n−2x−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 4 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and 1≦x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−2x, and each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent.
 12. The composition of claim 1, wherein the cyclic alkene has the general formula C_(n)H_(2n−(2x+2)−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 5 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−(2x+2), and each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent.
 13. The composition of claim 1, wherein the cyclic alkene has the general formula C_(n)H_(2n−(2x+4)−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 7 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−(2x+4), each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent.
 14. The composition of claim 1, wherein the cyclic alkene is at least one compound selected from the group consisting of dipentene, phellandrene, dicyclopentadiene, alpha-terpinene, gamma-terpinene, limonene, alpha-pinene, 3-carene, terpinolene, norbornene, norbornadiene, 5-vinyl-2-norbornene, and 5-ethylidene-2-norbornene.
 15. A composition, consisting essentially of: (a) at least one substituted or unsubstituted cyclic alkene having the general formula C_(n)H_(2n−2x−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 4 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and 1≦x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−2x, and each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent, and (b) an antioxidant composition comprising at least one compound of Formula (I),

wherein R¹ through R⁴ each independently is H, C₁-C₈ linear alkyl, C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈ linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈ cyclic alkoxy or substituted or unsubstituted aryl.
 16. The composition of claim 15, wherein one of R¹ through R⁴ is methyl, ethyl, methoxy, or ethoxy.
 17. The composition of claim 16, wherein at least one of the remaining R¹ through R⁴ is H.
 18. The composition of claim 16, wherein all of the remaining R¹ through R⁴ are H.
 19. The composition of claim 15, wherein R² or R³ is methyl or methoxy.
 20. The composition of claim 19, wherein at least one of the remaining R¹ through R⁴ are H.
 21. The composition of claim 15, wherein the antioxidant composition comprises 4-methyl-1,2-dihydroxybenzene.
 22. The composition of claim 15, wherein the antioxidant composition comprises 3-methoxy-1,2-dihydroxybenzene.
 23. The composition of claim 15, wherein the antioxidant composition is present in a concentration between about 1 ppm and about 200 ppm.
 24. The composition of claim 15, wherein the antioxidant composition is present in a concentration between about 50 ppm and about 150 ppm.
 25. The composition of claim 15, wherein the cyclic alkene is at least one compound selected from the group consisting of dipentene, limonene, terpinolene, phellandrene, alpha-terpinene, and gamma-terpinene.
 26. The composition of claim 15, wherein at least one of R¹ through R⁴ is not H, or if one of R¹ through R⁴ is t-butyl, at least one of the remaining R¹ through R⁴ is not H.
 27. A composition, consisting essentially of: (a) at least one substituted or unsubstituted cyclic alkene having the general formula C_(n)H_(2n−(2x+2)−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 5 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−(2x+2), and each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent, and (b) an antioxidant composition comprising at least one compound of Formula (I),

wherein R¹ through R⁴ each independently is H, C₁-C₈ linear alkyl, C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈ linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈ cyclic alkoxy or substituted or unsubstituted aryl.
 28. The composition of claim 27, wherein one of R¹ through R⁴ is methyl, ethyl, methoxy, or ethoxy.
 29. The composition of claim 27, wherein at least one of the remaining R¹ through R⁴ is H.
 30. The composition of claim 28, wherein all of the remaining R¹ through R⁴ are H.
 31. The composition of claim 27, wherein R² or R³ is methyl or methoxy.
 32. The composition of claim 31, wherein at least one of the remaining R¹ through R⁴ are H.
 33. The composition of claim 27, wherein the antioxidant composition comprises 4-methyl-1,2-dihydroxybenzene.
 34. The composition of claim 27, wherein the antioxidant composition comprises 3-methoxy-1,2-dihydroxybenzene.
 35. The composition of claim 27, wherein the antioxidant composition is present in a concentration between about 1 ppm and about 200 ppm.
 36. The composition of claim 27, wherein the antioxidant composition is present in a concentration between about 50 ppm and about 150 ppm.
 37. The composition of claim 27, wherein the cyclic alkene is at least one compound selected from the group consisting of alpha-pinene, 3-carene, norbornene, norbornadiene, 5-vinyl-2-norbornene, and 5-ethylidene-2-norbornene.
 38. The composition of claim 27, wherein at least one of R¹ through R⁴ is not H, or if one of R¹ through R⁴ is t-butyl, at least one of the remaining R¹ through R⁴ is not H.
 39. A composition, comprising: (a) a cyclic alkene selected from the group consisting of dipentene, phellandrene, dicyclopentadiene, alpha-terpinene, gamma-terpinene, limonene, alpha-pinene, 3-carene, terpinolene, norbornene, norbornadiene, 5-vinyl-2-norbornene, and 5-ethylidene-2-norbornene, and (b) an antioxidant composition comprising 4-methyl-1,2-dihydroxybenzene or 3-methoxy-1,2-dihydroxybenzene.
 40. The composition of claim 39, wherein the antioxidant composition comprises 4-methyl-1,2-dihydroxybenzene.
 41. The composition of claim 39, wherein the antioxidant composition is present in a concentration between about 1 ppm and about 200 ppm.
 42. The composition of claim 39, wherein the antioxidant composition is present in a concentration between about 50 ppm and about 150 ppm.
 43. A composition, comprising: (a) a substituted or unsubstituted cyclic alkene having the general formula C_(n)H_(2n−(2x+2)−y)R_(y), in which n is the number of carbons in the primary cyclic structure and is an integer from 5 to 18, x is the number of unsaturated sites in the primary cyclic structure and is an integer and x≦n/2, y is the number of substituents, R, on the primary cyclic structure and is an integer and 0≦y≦2n−(2x+2), and each R independently is C₁-C₁₈ linear alkyl, C₃-C₁₈ branched alkyl, C₂-C₁₈ unsaturated alkyl, C₃-C₁₈ cyclic alkyl, C₁-C₁₈ linear alkoxy, C₃-C₁₈ branched alkoxy, C₂-C₁₈ unsaturated alkoxy, C₃-C₁₈ cyclic alkoxy, substituted or unsubstituted aryl, or substituted silicon containing substituent, and (b) an antioxidant composition comprising at least one compound of Formula (I),

wherein R¹ through R⁴ each independently is H, C₁-C₈ linear alkyl, C₂-C₈ unsaturated alkyl, C₃-C₈ branched alkyl, C₃-C₈ cyclic alkyl, C₁-C₈ linear alkoxy, C₂-C₈ unsaturated alkoxy, C₃-C₈ branched alkoxy, C₃-C₈ cyclic alkoxy or substituted or unsubstituted aryl; wherein the composition comprises only one cyclic alkene. 